Methylnaltrexone is a methyl derivative of noroxymorphone with selective, opioid-receptor antagonistic activity. Methylnaltrexone is a member of phenanthrenes. Methylnaltrexone displaces opioids from peripheral opioid receptors in the gastrointestinal tract, the bladder, and the skin, resulting in decreases in opioid-related constipation, urinary retention, and pruritis, respectively. Methylnaltrexone does not cross the blood-brain barrier and does not affect the centrally-mediated analgesic effect of opioids.
Methylnaltrexone Bromide is the bromide salt form of methylnaltrexone, a methyl derivative of noroxymorphone with selective, peripherally-acting mu-opioid receptor antagonistic activity. Methylnaltrexone displaces opioids from peripheral opioid receptors in the gastrointestinal tract, the bladder, and the skin, thereby reversing the opioid-related peripheral side effects, such as constipation, urinary retention, and pruritis, respectively. Unlike naltrexone and due to the presence of a positively charged nitrogen atom in methylnaltrexone, this agent does not cross the blood-brain barrier and does not affect the centrally-mediated analgesic effect of opioids.
Methylnaltrexone is a methyl derivative of noroxymorphone with selective, opioid-receptor antagonistic activity. Methylnaltrexone displaces opioids from peripheral opioid receptors in the gastrointestinal tract, the bladder, and the skin, resulting in decreases in opioid-related constipation, urinary retention, and pruritis, respectively. Methylnaltrexone does not cross the blood-brain barrier and does not affect the centrally-mediated analgesic effect of opioids.
Mechanism of action
Methylnaltrexone is a peripherally-acting μ-opioid antagonist that acts on the gastrointestinal tract and inhibits an opioid-induced decrease in gastric motility and transit time. Because methylnaltrexone is a quaternary derivative of naltrexone, it produces its gastrointestinal effects without producing analgesic effects or withdrawal symptoms as it does not cross the blood-brain barrier.
Use of opioids induces slowing of gastrointestinal motility and transit. Following remifentanil administration, the methylnaltrexone and placebo groups showed no change in pupillary constriction while the naloxone group showed a marked change over the time interval tested.
Methylnaltrexone is a peripheral-acting mu-opioid receptor antagonist and does not cross the blood-brain barrier.[rx] Methylnaltrexone has restricted access through the blood-brain barrier because it is a quaternary amine, which carries a positive charge when in a solution and more has polarity with lower lipid solubility than a lot of the opioid agonists used for pain treatment.[rx] The peripheral action of methylnaltrexone makes it effective for decreasing the constipating effects of opioids, without interfering with the analgesic effects (of opioids) on the central nervous system.[rx] This is the primary characteristic that makes methylnaltrexone behave differently than naltrexone.[10]
Furthermore, as methylnaltrexone cannot cross the blood–brain barrier, it does not reverse the pain-killing properties of opioid agonists or cause withdrawal symptoms, but since a small portion of analgesia comes from the peripheral opioid receptors, it can increase pain from inflammatory conditions such as arthritis.
Indications
- Treatment of opioid-induced constipation in advanced-illness patients who are receiving palliative care when the response to usual laxative therapy has not been sufficient.
- For the treatment of opioid-induced constipation in adult patients with chronic non-cancer pain or advanced illness who are receiving palliative care, when the response to laxative therapy has not been sufficient.
Use in Cancer
Methylnaltrexone bromide is approved to treat:
- Constipation is caused by the use of opioids. It is used in adults with pain caused by cancer or treatment for cancer or by another advanced disease.
Contraindications
- cancer of the stomach or intestines
- stomach or intestinal ulcer
- blockage of the stomach or intestine
- liver problems
- excessive diarrhea
- chronic diarrhea
- an enlargement of the intestine with stopped bowel function called megacolon
- chronic kidney disease stage 3A (moderate)
- chronic kidney disease stage 3B (moderate)
- chronic kidney disease stage 4 (severe)
- chronic kidney disease stage 5 (failure)
- Child-Pugh class C liver impairment
Dosage
Strengths: 12 mg/0.6 mL; 150 mg; 8 mg/0.4 mL
Constipation – Drug-Induced
Opioid-Induced Constipation in Patients with Chronic Non-Cancer Pain:
- Oral: 450 mg orally once a day in the morning
- Parenteral: 12 mg subcutaneously once a day
- Prior to initiation, discontinue all maintenance laxative therapy; laxatives can be used as needed for suboptimal response after 3 days.
- Patients should be within close proximity to a bathroom once this drug is administered.
- Re-evaluate the continued need for this drug when the opioid regimen is changed to avoid adverse reactions.
Opioid-Induced Constipation in Patients with Advanced Illness:
Parenteral: Weight-based dosing: Administer subcutaneously every other day as needed, but no more frequently than 1 dose in a 24-hour period:
- Less than 38 kg: 0.15 mg/kg
- 38 kg to less than 62 kg: 8 mg (0.4 mL)
- 62 kg to 114 kg: 12 mg subcutaneously (0.6 mL)
- More than 114 kg: 0.15 mg/kg subcutaneously
- To determine injection volume for patients whose weight is less than 38 kg or more than 114 kg: multiply patient weight (kg) by 0.0075 and round up to the nearest 0.1 mL
Renal Dose Adjustments
Moderate to severe renal impairment (CrCl less than 60 mL/min):
Chronic Non-Cancer Pain:
- Oral: 150 mg orally once a day in the morning
- Parenteral: 6 mg subcutaneously once a day
Advanced Illness:
Parenteral: weight-based dosing:
- Less than 38 kg: 0.075 mg/kg subcutaneously every other day
- 38 to less than 62 kg: 4 mg subcutaneously every other day
- 62 to 114 kg: 6 mg subcutaneously every other day
- Greater than 114 kg: 0.075 mg/kg subcutaneously every other day
- To determine injection volume for patients whose weight is less than 38 kg or more than 114 kg: multiply patient weight (kg) by 0.0075 and round up to the nearest 0.1 mL
Liver Dose Adjustments
Moderate to severe hepatic impairment (Child-Pugh Class B or C):
- Chronic Non-Cancer Pain: Oral: 150 mg orally once a day in the morning
Severe hepatic impairment: Chronic Non-Cancer Pain or Advanced illness:
- Parenteral: Weight-based dosing:
- Less than 38 kg: 0.075 mg/kg subcutaneously every other day
- 38 to less than 62 kg: 4 mg subcutaneously every other day
- 62 to 114 kg: 6 mg subcutaneously every other day
- Greater than 114 kg: 0.075 mg/kg subcutaneously every other day
- To determine injection volume for patients whose weight is less than 38 kg or more than 114 kg: multiply patient weight (kg) by 0.0075 and round up to the nearest 0.1 mL
General:
- If treatment with opioid pain medication is discontinued, this drug should be discontinued; if the opioid regimen is changed, re-evaluate the continued need of this drug.
- In clinical trials in patients with advanced illness, this drug was administered concomitantly with a laxative regimen.
- In patients with chronic non-cancer pain, all maintenance laxative therapy should be discontinued prior to initiating therapy; laxatives can be used as needed after 3 days.
- This drug has been shown to be efficacious in patients who have taken opioids for at least 4 weeks; sustained exposure to opioids prior to starting this drug may increase the patient’s sensitivity to this drug
Patient advice:
- Patients should be instructed to be within close proximity to toilet facilities once this drug is taken.
- Patients should be instructed to seek medical attention promptly if unusually severe, persistent, or worsening abdominal pain or diarrhea develops.
- Patients should understand that symptoms of opioid withdrawal such as sweating, chills, anxiety, irritability, and yawning may occur.
- Patients should speak to health care professionals if they become pregnant, intend to become pregnant, or are breastfeeding.
Side Effects
The Most Common
- vomiting
- sweating
- chills
- anxiety
- yawning
- headache
- abdominal pain and swelling
- muscle spasms
- runny nose
- severe diarrhea
- severe abdominal pain
More Common
- severe or ongoing diarrhea;
- extreme dizziness, or feeling like you might pass out;
- bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
- nausea or vomiting that are new or worsening symptoms; or
- symptoms of opioid medicine withdrawal–anxiety, sweating, chills, yawning, stomach pain, diarrhea.
- stomach pain, gas, bloating;
- mild nausea or diarrhea;
- headache, muscle spasms;
- dizziness, tremors, feeling anxious;
- runny nose; or
- chills, sweating, or hot flashes.
- Chills
- diarrhea
- fear or nervousness
- increased sweating
- severe abdominal or stomach pain
- severe or persistent diarrhea
- yawning
Rare
- Full or bloated feeling
- headache
- muscle spasms
- pressure in the stomach
- runny nose
- swelling of the abdominal or stomach area
- vomiting
Drug Interactions
| DRUG | INTERACTION |
|---|---|
| Abacavir | Abacavir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Aceclofenac | Aceclofenac may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Acemetacin | Acemetacin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Acetaminophen | Acetaminophen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Acetazolamide | Acetazolamide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Acetylsalicylic acid | Acetylsalicylic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Aclidinium | Methylnaltrexone may decrease the excretion rate of Aclidinium which could result in a higher serum level. |
| Acrivastine | Methylnaltrexone may decrease the excretion rate of Acrivastine which could result in a higher serum level. |
| Acyclovir | Acyclovir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Adefovir dipivoxil | Adefovir dipivoxil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Albutrepenonacog | Methylnaltrexone may decrease the excretion rate of Albutrepenonacog alfa which could result in a higher serum level. |
| Alclofenac | Alclofenac may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Aldesleukin | Aldesleukin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Alfentanil | The therapeutic efficacy of Alfentanil can be decreased when used in combination with Methylnaltrexone. |
| Allopurinol | Allopurinol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Almasilate | Methylnaltrexone may decrease the excretion rate of Almasilate which could result in a higher serum level. |
| Almotriptan | Almotriptan may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Alogliptin | Alogliptin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Alprazolam | Alprazolam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Alvimopan | Alvimopan may increase the opioid antagonism activities of Methylnaltrexone. |
| Amantadine | Amantadine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Amikacin | Methylnaltrexone may decrease the excretion rate of Amikacin which could result in a higher serum level. |
| Amiloride | Amiloride may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Aminophenazone | Aminophenazone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Amitriptyline | Amitriptyline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ammonium chloride | Ammonium chloride may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Amoxicillin | Amoxicillin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Amphetamine | Amphetamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Amphotericin B | Amphotericin B may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ampicillin | Ampicillin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Amrinone | Amrinone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ancestim | Methylnaltrexone may decrease the excretion rate of Ancestim which could result in a higher serum level. |
| Antihemophilic | Methylnaltrexone may decrease the excretion rate of Antihemophilic factor (recombinant), PEGylated which could result in a higher serum level. |
| Antipyrine | Antipyrine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Antithrombin III human | Methylnaltrexone may decrease the excretion rate of Antithrombin III human which could result in a higher serum level. |
| Antrafenine | Antrafenine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Apalutamide | Methylnaltrexone may decrease the excretion rate of Apalutamide which could result in a higher serum level. |
| Apremilast | Apremilast may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Arformoterol | Arformoterol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Arsenic trioxide | Arsenic trioxide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Atazanavir | Atazanavir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Atomoxetine | Atomoxetine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Auranofin | Auranofin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Aurothioglucose | Methylnaltrexone may decrease the excretion rate of Aurothioglucose which could result in a higher serum level. |
| Azacitidine | Azacitidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Azathioprine | Azathioprine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Azelaic acid | Azelaic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Aztreonam | Aztreonam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bacitracin | Bacitracin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Baclofen | Baclofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Balsalazide | Balsalazide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Baricitinib | Methylnaltrexone may decrease the excretion rate of Baricitinib which could result in a higher serum level. |
| Bendroflumethiazide | Bendroflumethiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Benorilate | Benorilate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Benoxaprofen | Benoxaprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Benserazide | Methylnaltrexone may decrease the excretion rate of Benserazide which could result in a higher serum level. |
| Benzatropine | Benzatropine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Benzhydrocodone | The therapeutic efficacy of Benzhydrocodone can be decreased when used in combination with Methylnaltrexone. |
| Benznidazole | Methylnaltrexone may decrease the excretion rate of Benznidazole which could result in a higher serum level. |
| Benzthiazide | Benzthiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Benzydamine | Benzydamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bepotastine | Bepotastine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bicisate | Methylnaltrexone may decrease the excretion rate of Bicisate which could result in a higher serum level. |
| Bismuth subgallate | Methylnaltrexone may decrease the excretion rate of Bismuth subgallate which could result in a higher serum level. |
| Bisoprolol | Bisoprolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bisoxatin | Methylnaltrexone may decrease the excretion rate of Bisoxatin which could result in a higher serum level. |
| Bleomycin | Bleomycin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Brivaracetam | Brivaracetam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bromazepam | Bromazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bromotheophylline | Bromotheophylline may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Budesonide | Budesonide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bumadizone | Bumadizone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Bumetanide | Bumetanide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Buprenorphine | Buprenorphine may increase the opioid antagonism activities of Methylnaltrexone. |
| Bupropion | Bupropion may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Buspirone | Buspirone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Butabarbital | Butabarbital may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Butorphanol | Butorphanol may increase the opioid antagonism activities of Methylnaltrexone. |
| Canagliflozin | Methylnaltrexone may decrease the excretion rate of Canagliflozin which could result in a higher serum level. |
| Canrenoic acid | Canrenoic acid may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Capecitabine | Capecitabine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Capreomycin | Methylnaltrexone may decrease the excretion rate of Capreomycin which could result in a higher serum level. |
| Carbamazepine | Methylnaltrexone may decrease the excretion rate of Carbamazepine which could result in a higher serum level. |
| Carbidopa | Carbidopa may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Carboplatin | Carboplatin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Carmustine | Carmustine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Carprofen | Carprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefaclor | Cefaclor may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefadroxil | Cefadroxil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefalotin | Cefalotin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefamandole | Cefamandole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefapirin | Cefapirin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefazolin | Cefazolin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefdinir | Cefdinir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefditoren | Cefditoren may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefepime | Cefepime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefmenoxime | Cefmenoxime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefmetazole | Cefmetazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefonicid | Cefonicid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefoperazone | Cefoperazone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceforanide | Ceforanide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefotaxime | Cefotaxime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefotetan | Cefotetan may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefotiam | Cefotiam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefoxitin | Cefoxitin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefpiramide | Cefpiramide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefpirome | Cefpirome may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefpodoxime | Cefpodoxime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefprozil | Cefprozil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefradine | Cefradine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceftaroline | Ceftaroline fosamil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceftazidime | Ceftazidime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceftibuten | Ceftibuten may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceftizoxime | Ceftizoxime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceftobiprole | Ceftobiprole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ceftolozane | Methylnaltrexone may decrease the excretion rate of Ceftolozane which could result in a higher serum level. |
| Ceftriaxone | Ceftriaxone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cefuroxime | Cefuroxime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Celecoxib | Celecoxib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cephalexin | Cephalexin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cephaloglycin | Cephaloglycin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Certolizumab | Methylnaltrexone may decrease the excretion rate of Certolizumab pegol which could result in a higher serum level. |
| Cetirizine | Cetirizine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cevimeline | Cevimeline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Chloral hydrate | Chloral hydrate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Chloroquine | Chloroquine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Chlorothiazide | Chlorothiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Chlorpromazine | Chlorpromazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Chlorpropamide | Chlorpropamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Chlorthalidone | Chlorthalidone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Chlorzoxazone | Chlorzoxazone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Choline C 11 | Methylnaltrexone may decrease the excretion rate of Choline C 11 which could result in a higher serum level. |
| Choline magnesium | Choline magnesium trisalicylate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Choline salicylate | Methylnaltrexone may decrease the excretion rate of Choline salicylate which could result in a higher serum level. |
| Chondroitin sulfate | Methylnaltrexone may decrease the excretion rate of Chondroitin sulfate which could result in a higher serum level. |
| Chromic chloride | Methylnaltrexone may decrease the excretion rate of Chromic chloride which could result in a higher serum level. |
| Chromic nitrate | Methylnaltrexone may decrease the excretion rate of Chromic nitrate which could result in a higher serum level. |
| Chromium | Methylnaltrexone may decrease the excretion rate of Chromium which could result in a higher serum level. |
| Chromium gluconate | Methylnaltrexone may decrease the excretion rate of Chromium gluconate which could result in a higher serum level. |
| Chromium nicotinate | Methylnaltrexone may decrease the excretion rate of Chromium nicotinate which could result in a higher serum level. |
| Chromous sulfate | Methylnaltrexone may decrease the excretion rate of Chromous sulfate which could result in a higher serum level. |
| Cidofovir | Cidofovir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cilostazol | Cilostazol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cimetidine | Cimetidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ciprofloxacin | Ciprofloxacin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cisplatin | Methylnaltrexone may decrease the excretion rate of Cisplatin which could result in a higher serum level. |
| Clevidipine | Clevidipine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Clobazam | Clobazam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Clofarabine | Clofarabine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Clomipramine | Clomipramine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Clonazepam | Clonazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Clorazepic acid | Clorazepic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Clove oil | Methylnaltrexone may decrease the excretion rate of Clove oil which could result in a higher serum level. |
| Clozapine | Clozapine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Codeine | The therapeutic efficacy of Codeine can be decreased when used in combination with Methylnaltrexone. |
| Colchicine | Colchicine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Colistimethate | Colistimethate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Colistin | Methylnaltrexone may decrease the excretion rate of Colistin which could result in a higher serum level. |
| Conivaptan | Conivaptan may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Conjugated estrogens | Conjugated estrogens may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Corifollitropin alfa | Methylnaltrexone may decrease the excretion rate of Corifollitropin alfa which could result in a higher serum level. |
| Cyanocobalamin | Cyanocobalamin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cyclopenthiazide | Cyclopenthiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Cyclosporine | Cyclosporine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Cyclothiazide | Cyclothiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Dabigatran etexilate | Dabigatran etexilate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dacarbazine | Dacarbazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dalfampridine | Dalfampridine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Daptomycin | Daptomycin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Deferiprone | Methylnaltrexone may decrease the excretion rate of Deferiprone which could result in a higher serum level. |
| Delafloxacin | Methylnaltrexone may decrease the excretion rate of Delafloxacin which could result in a higher serum level. |
| Desipramine | Desipramine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Desmopressin | Desmopressin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Desvenlafaxine | Desvenlafaxine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Deutetrabenazine | Methylnaltrexone may decrease the excretion rate of Deutetrabenazine which could result in a higher serum level. |
| Dexibuprofen | Dexibuprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dexketoprofen | Dexketoprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dexmedetomidine | Dexmedetomidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dexpanthenol | Methylnaltrexone may decrease the excretion rate of Dexpanthenol which could result in a higher serum level. |
| Dexrazoxane | Dexrazoxane may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dextran | Methylnaltrexone may decrease the excretion rate of Dextran which could result in a higher serum level. |
| Dextropropoxyphene | The therapeutic efficacy of Dextropropoxyphene can be decreased when used in combination with Methylnaltrexone. |
| Dezocine | Dezocine may increase the opioid antagonism activities of Methylnaltrexone. |
| Diamorphine | The therapeutic efficacy of Diamorphine can be decreased when used in combination with Methylnaltrexone. |
| Diatrizoate | Diatrizoate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Diazepam | Diazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dichlorobenzyl alcohol | Methylnaltrexone may decrease the excretion rate of Dichlorobenzyl alcohol which could result in a higher serum level. |
| Diclofenac | Diclofenac may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Diclofenamide | Diclofenamide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Dicyclomine | Dicyclomine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Didanosine | Didanosine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dienogest | Methylnaltrexone may decrease the excretion rate of Dienogest which could result in a higher serum level. |
| Diflunisal | Diflunisal may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Difluocortolone | Methylnaltrexone may decrease the excretion rate of Difluocortolone which could result in a higher serum level. |
| Digoxin | Methylnaltrexone may decrease the excretion rate of Digoxin which could result in a higher serum level. |
| Dihydrocodeine | The therapeutic efficacy of Dihydrocodeine can be decreased when used in combination with Methylnaltrexone. |
| Dihydrostreptomycin | Dihydrostreptomycin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dimercaprol | Dimercaprol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dimethyl sulfoxide | Dimethyl sulfoxide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Diphenoxylate | The therapeutic efficacy of Diphenoxylate can be decreased when used in combination with Methylnaltrexone. |
| Disopyramide | Disopyramide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| DL-Methylephedrine | Methylnaltrexone may decrease the excretion rate of DL-Methylephedrine which could result in a higher serum level. |
| Dobutamine | Dobutamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dopamine | Dopamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Doripenem | Doripenem may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Doxacurium | Doxacurium may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Doxepin | Doxepin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Doxycycline | Doxycycline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Drospirenone | Drospirenone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Droxidopa | Droxidopa may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Duloxetine | Duloxetine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Dyphylline | Dyphylline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Edoxaban | Methylnaltrexone may decrease the excretion rate of Edoxaban which could result in a higher serum level. |
| Edrophonium | Edrophonium may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Eluxadoline | Eluxadoline may increase the opioid antagonism activities of Methylnaltrexone. |
| Enalaprilat | Methylnaltrexone may decrease the excretion rate of Enalaprilat which could result in a higher serum level. |
| Enzalutamide | Methylnaltrexone may decrease the excretion rate of Enzalutamide which could result in a higher serum level. |
| Eplerenone | Eplerenone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Epoprostenol | Epoprostenol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ertapenem | Ertapenem may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Estazolam | Estazolam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Estradiol | Estradiol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Estradiol acetate | Methylnaltrexone may decrease the excretion rate of Estradiol acetate which could result in a higher serum level. |
| Estradiol cypionate | Methylnaltrexone may decrease the excretion rate of Estradiol cypionate which could result in a higher serum level. |
| Estradiol dienanthate | Methylnaltrexone may decrease the excretion rate of Estradiol dienanthate which could result in a higher serum level. |
| Estradiol valerate | Methylnaltrexone may decrease the excretion rate of Estradiol valerate which could result in a higher serum level. |
| Estrone sulfate | Estrone sulfate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Eszopiclone | Eszopiclone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Etacrynic acid | Etacrynic acid may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Etafedrine | Methylnaltrexone may decrease the excretion rate of Etafedrine which could result in a higher serum level. |
| Ethambutol | Ethambutol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Etodolac | Etodolac may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Etomidate | Etomidate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Etonogestrel | Etonogestrel may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Etoricoxib | Etoricoxib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Eucalyptus oil | Methylnaltrexone may decrease the excretion rate of Eucalyptus oil which could result in a higher serum level. |
| Ezogabine | Ezogabine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fenbufen | Fenbufen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fenofibrate | Fenofibrate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fenofibric acid | Methylnaltrexone may decrease the excretion rate of Fenofibric acid which could result in a higher serum level. |
| Fenoldopam | Fenoldopam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fenoprofen | Fenoprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fentanyl | The therapeutic efficacy of Fentanyl can be decreased when used in combination with Methylnaltrexone. |
| Fesoterodine | Fesoterodine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Finerenone | Finerenone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Flavoxate | Flavoxate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Floctafenine | Floctafenine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Florbetaben (18F) | Methylnaltrexone may decrease the excretion rate of Florbetaben (18F) which could result in a higher serum level. |
| Florbetapir (18F) | Methylnaltrexone may decrease the excretion rate of Florbetapir (18F) which could result in a higher serum level. |
| Floxuridine | Floxuridine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fluconazole | Fluconazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Flucytosine | Flucytosine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fludeoxyglucose (18F) | Methylnaltrexone may decrease the excretion rate of Fludeoxyglucose (18F) which could result in a higher serum level. |
| Flumazenil | Flumazenil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fluocinolone acetonide | Fluocinolone acetonide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Flurazepam | Flurazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Flurbiprofen | Flurbiprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Flutamide | Flutamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fluvoxamine | Fluvoxamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Folic acid | Folic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fomepizole | Fomepizole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fondaparinux | Fondaparinux may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Formestane | Methylnaltrexone may decrease the excretion rate of Formestane which could result in a higher serum level. |
| Foscarnet | Foscarnet may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fosfomycin | Fosfomycin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Fosinopril | Fosinopril may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Framycetin | Framycetin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Furosemide | Furosemide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Gabapentin enacar | Methylnaltrexone may decrease the excretion rate of Gabapentin enacarbil which could result in a higher serum level. |
| Gadobenic acid | Gadobenic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gadodiamide | Gadodiamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gadofosveset trisodium | Gadofosveset trisodium may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gadopentetic acid | Gadopentetic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gadoteric acid | Methylnaltrexone may decrease the excretion rate of Gadoteric acid which could result in a higher serum level. |
| Gadoteridol | Gadoteridol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ganciclovir | Ganciclovir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gemcitabine | Gemcitabine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gemfibrozil | Gemfibrozil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Gentamicin | Methylnaltrexone may decrease the excretion rate of Gentamicin which could result in a higher serum level. |
| Gimeracil | Methylnaltrexone may decrease the excretion rate of Gimeracil which could result in a higher serum level. |
| Givosiran | Givosiran may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Glipizide | Glipizide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Glycerol phenylbutyrate | Methylnaltrexone may decrease the excretion rate of Glycerol phenylbutyrate which could result in a higher serum level. |
| Golodirsen | Methylnaltrexone may decrease the excretion rate of Golodirsen which could result in a higher serum level. |
| Goserelin | Goserelin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Guanethidine | Guanethidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Guanfacine | Guanfacine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Haloperidol | Haloperidol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Hydralazine | Hydralazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Hydrochlorothiazide | Hydrochlorothiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Hydrocodone | The therapeutic efficacy of Hydrocodone can be decreased when used in combination with Methylnaltrexone. |
| Hydroflumethiazide | Hydroflumethiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Hydromorphone | The therapeutic efficacy of Hydromorphone can be decreased when used in combination with Methylnaltrexone. |
| Hydroxocobalamin | Hydroxocobalamin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Hydroxyethyl Starch | Methylnaltrexone may decrease the excretion rate of Hydroxyethyl Starch which could result in a higher serum level. |
| Ibuprofen | Ibuprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ibutilide | Ibutilide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Icatibant | Icatibant may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Icosapent | Icosapent may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Idarucizumab | Methylnaltrexone may decrease the excretion rate of Idarucizumab which could result in a higher serum level. |
| Idebenone | Methylnaltrexone may decrease the excretion rate of Idebenone which could result in a higher serum level. |
| Ifosfamide | Ifosfamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Imipramine | Imipramine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Indapamide | Indapamide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Indigotindisulfonic | Methylnaltrexone may decrease the excretion rate of Indigotindisulfonic acid which could result in a higher serum level. |
| Indomethacin | Indomethacin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Inosine pranobex | Methylnaltrexone may decrease the excretion rate of Inosine pranobex which could result in a higher serum level. |
| Inositol | Methylnaltrexone may decrease the excretion rate of Inositol which could result in a higher serum level. |
| Inotersen | Inotersen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Iobenguane sulfate | Methylnaltrexone may decrease the excretion rate of Iobenguane sulfate I-123 which could result in a higher serum level. |
| Iodixanol | Iodixanol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ioflupane I-123 | Methylnaltrexone may decrease the excretion rate of Ioflupane I-123 which could result in a higher serum level. |
| Iopromide | Methylnaltrexone may decrease the excretion rate of Iopromide which could result in a higher serum level. |
| Iothalamic acid | Methylnaltrexone may decrease the excretion rate of Iothalamic acid which could result in a higher serum level. |
| Ioversol | Methylnaltrexone may decrease the excretion rate of Ioversol which could result in a higher serum level. |
| Ioxilan | Methylnaltrexone may decrease the excretion rate of Ioxilan which could result in a higher serum level. |
| Ipecac | Methylnaltrexone may decrease the excretion rate of Ipecac which could result in a higher serum level. |
| Ipilimumab | Ipilimumab may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Isoniazid | Isoniazid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Isosorbide | Isosorbide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Isosorbide mononi | Isosorbide mononitrate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Isosulfan blue | Methylnaltrexone may decrease the excretion rate of Isosulfan blue which could result in a higher serum level. |
| Isotretinoin | Isotretinoin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Isoxicam | Isoxicam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Isradipine | Isradipine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ixazomib | Methylnaltrexone may decrease the excretion rate of Ixazomib which could result in a higher serum level. |
| Kanamycin | Methylnaltrexone may decrease the excretion rate of Kanamycin which could result in a higher serum level. |
| Ketamine | Ketamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ketazolam | Ketazolam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ketoprofen | Ketoprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ketorolac | Ketorolac may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Labetalol | Labetalol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lamivudine | Lamivudine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lamotrigine | Lamotrigine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Latamoxef | Latamoxef may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ledipasvir | Methylnaltrexone may decrease the excretion rate of Ledipasvir which could result in a higher serum level. |
| Lenalidomide | Lenalidomide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lesinurad | Methylnaltrexone may decrease the excretion rate of Lesinurad which could result in a higher serum level. |
| Leuprolide | Leuprolide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Levacetylmethadol | The therapeutic efficacy of Levacetylmethadol can be decreased when used in combination with Methylnaltrexone. |
| Levallorphan | Levallorphan may increase the opioid antagonism activities of Methylnaltrexone. |
| Levobupivacaine | Levobupivacaine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Levocarnitine | Levocarnitine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Levocetirizine | Levocetirizine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Levofloxacin | Levofloxacin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Levomilnacipran | Methylnaltrexone may decrease the excretion rate of Levomilnacipran which could result in a higher serum level. |
| Levorphanol | The therapeutic efficacy of Levorphanol can be decreased when used in combination with Methylnaltrexone. |
| Levosalbutamol | Methylnaltrexone may decrease the excretion rate of Levosalbutamol which could result in a higher serum level. |
| Liothyronine | Liothyronine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lisinopril | Lisinopril may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lithium carbonate | Methylnaltrexone may decrease the excretion rate of Lithium carbonate which could result in a higher serum level. |
| Lithium citrate | Lithium citrate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lixisenatide | Methylnaltrexone may decrease the excretion rate of Lixisenatide which could result in a higher serum level. |
| Lofexidine | Lofexidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lopinavir | Lopinavir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Loracarbef | Loracarbef may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lorazepam | Lorazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lorcaserin | Lorcaserin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lornoxicam | Lornoxicam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lorpiprazole | Methylnaltrexone may decrease the excretion rate of Lorpiprazole which could result in a higher serum level. |
| Loxoprofen | Loxoprofen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lubiprostone | Lubiprostone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Lumiracoxib | Lumiracoxib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Macitentan | Methylnaltrexone may decrease the excretion rate of Macitentan which could result in a higher serum level. |
| Magnesium carbonate | Methylnaltrexone may decrease the excretion rate of Magnesium carbonate which could result in a higher serum level. |
| Magnesium chloride | Methylnaltrexone may decrease the excretion rate of Magnesium chloride which could result in a higher serum level. |
| Magnesium hydroxide | Methylnaltrexone may decrease the excretion rate of Magnesium hydroxide which could result in a higher serum level. |
| Magnesium trisilicate | Methylnaltrexone may decrease the excretion rate of Magnesium trisilicate which could result in a higher serum level. |
| Mangafodipir | Mangafodipir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Mannitol | Mannitol may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Maprotiline | Maprotiline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Mecamylamine | Mecamylamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Meclofenamic acid | Meclofenamic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Medroxyprogesterone | Medroxyprogesterone acetate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Mefenamic acid | Mefenamic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Megestrol acetate | Megestrol acetate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Meloxicam | Meloxicam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Memantine | Memantine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Meperidine | The therapeutic efficacy of Meperidine can be decreased when used in combination with Methylnaltrexone. |
| Mepivacaine | Mepivacaine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Meropenem | Meropenem may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Mesalazine | Mesalazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Metamfetamine | Metamfetamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Metamizole | Metamizole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Metaxalone | Metaxalone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Metformin | Metformin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Methadone | The therapeutic efficacy of Methadone can be decreased when used in combination with Methylnaltrexone. |
| Methazolamide | Methazolamide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Methimazole | Methimazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Methotrexate | Methotrexate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Methoxsalen | Methoxsalen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Methyldopa | Methyldopa may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Methylene blue | Methylnaltrexone may decrease the excretion rate of Methylene blue which could result in a higher serum level. |
| Methyltestosterone | Methyltestosterone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Meticrane | Meticrane may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Metoclopramide | Metoclopramide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Metolazone | Metolazone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Metoprolol | Metoprolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Metyrapone | Metyrapone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Midazolam | Midazolam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Migalastat | Migalastat may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Milnacipran | Milnacipran may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Milrinone | Milrinone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Mirabegron | Methylnaltrexone may decrease the excretion rate of Mirabegron which could result in a higher serum level. |
| Morphine | The therapeutic efficacy of Morphine can be decreased when used in combination with Methylnaltrexone. |
| Moxisylyte | Methylnaltrexone may decrease the excretion rate of Moxisylyte which could result in a higher serum level. |
| Muzolimine | Muzolimine may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Mycophenolate mofetil | Mycophenolate mofetil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Mycophenolic acid | Mycophenolic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| N-acetyltyrosine | Methylnaltrexone may decrease the excretion rate of N-acetyltyrosine which could result in a higher serum level. |
| Nabumetone | Nabumetone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nadolol | Nadolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nalbuphine | Nalbuphine may increase the opioid antagonism activities of Methylnaltrexone. |
| Naldemedine | Naldemedine may increase the opioid antagonism activities of Methylnaltrexone. |
| Nalmefene | Nalmefene may increase the opioid antagonism activities of Methylnaltrexone. |
| Naloxegol | Naloxegol may increase the opioid antagonism activities of Methylnaltrexone. |
| Naloxone | Naloxone may increase the opioid antagonism activities of Methylnaltrexone. |
| Naltrexone | Naltrexone may increase the opioid antagonism activities of Methylnaltrexone. |
| Naproxen | Naproxen may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nateglinide | Nateglinide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nedaplatin | Methylnaltrexone may decrease the excretion rate of Nedaplatin which could result in a higher serum level. |
| Nedocromil | Nedocromil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nefazodone | Nefazodone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Neomycin | Methylnaltrexone may decrease the excretion rate of Neomycin which could result in a higher serum level. |
| Netilmicin | Methylnaltrexone may decrease the excretion rate of Netilmicin which could result in a higher serum level. |
| Nicorandil | Methylnaltrexone may decrease the excretion rate of Nicorandil which could result in a higher serum level. |
| Nifedipine | Nifedipine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nilutamide | Nilutamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nimesulide | Nimesulide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nisoldipine | Nisoldipine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nitric Oxide | Nitric Oxide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nitrofurantoin | Nitrofurantoin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Nitroprusside | Nitroprusside may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Normethadone | The therapeutic efficacy of Normethadone can be decreased when used in combination with Methylnaltrexone. |
| Octinoxate | Methylnaltrexone may decrease the excretion rate of Octinoxate which could result in a higher serum level. |
| Oliceridine | The therapeutic efficacy of Oliceridine can be decreased when used in combination with Methylnaltrexone. |
| Olsalazine | Olsalazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Opium | The therapeutic efficacy of Opium can be decreased when used in combination with Methylnaltrexone. |
| Oseltamivir | Oseltamivir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Oxacillin | Oxacillin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Oxaprozin | Oxaprozin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Oxazepam | Oxazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Oxybenzone | Oxybenzone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Oxycodone | The therapeutic efficacy of Oxycodone can be decreased when used in combination with Methylnaltrexone. |
| Oxymorphone | The therapeutic efficacy of Oxymorphone can be decreased when used in combination with Methylnaltrexone. |
| Oxyphenbutazone | Oxyphenbutazone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Oxyquinoline | Methylnaltrexone may decrease the excretion rate of Oxyquinoline which could result in a higher serum level. |
| Paliperidone | Paliperidone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Palonosetron | Palonosetron may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pamidronic acid | Pamidronic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pantoprazole | Pantoprazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Parecoxib | Parecoxib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Paromomycin | Paromomycin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Patent Blue | Methylnaltrexone may decrease the excretion rate of Patent Blue which could result in a higher serum level. |
| Pegaptanib | Pegaptanib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Peginesatide | Methylnaltrexone may decrease the excretion rate of Peginesatide which could result in a higher serum level. |
| Pemetrexed | Methylnaltrexone may decrease the excretion rate of Pemetrexed which could result in a higher serum level. |
| Penbutolol | Penbutolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pentaerythritol t | Pentaerythritol tetranitrate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pentamidine | Pentamidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pentastarch | Methylnaltrexone may decrease the excretion rate of Pentastarch which could result in a higher serum level. |
| Pentazocine | Pentazocine may increase the opioid antagonism activities of Methylnaltrexone. |
| Pentetic acid | Methylnaltrexone may decrease the excretion rate of Pentetic acid which could result in a higher serum level. |
| Pentobarbital | Pentobarbital may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pentostatin | Methylnaltrexone may decrease the excretion rate of Pentostatin which could result in a higher serum level. |
| Pentoxifylline | Pentoxifylline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Perindopril | Perindopril may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Permethrin | Permethrin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Phenazopyridine | Phenazopyridine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Phenelzine | Phenelzine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Phentolamine | Phentolamine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Phenylbutazone | Phenylbutazone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pholcodine | Methylnaltrexone may decrease the excretion rate of Pholcodine which could result in a higher serum level. |
| Phosphoric acid | Methylnaltrexone may decrease the excretion rate of Phosphoric acid which could result in a higher serum level. |
| Phylloquinone | Phylloquinone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Picosulfuric acid | Methylnaltrexone may decrease the excretion rate of Picosulfuric acid which could result in a higher serum level. |
| Pindolol | Pindolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Piperacillin | Piperacillin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Piracetam | Methylnaltrexone may decrease the excretion rate of Piracetam which could result in a higher serum level. |
| Piretanide | Piretanide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Piritramide | The therapeutic efficacy of Piritramide can be decreased when used in combination with Methylnaltrexone. |
| Piroxicam | Piroxicam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pitolisant | Methylnaltrexone may decrease the excretion rate of Pitolisant which could result in a higher serum level. |
| Plazomicin | Methylnaltrexone may decrease the excretion rate of Plazomicin which could result in a higher serum level. |
| Plerixafor | Methylnaltrexone may decrease the excretion rate of Plerixafor which could result in a higher serum level. |
| Polythiazide | Polythiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Pomalidomide | Methylnaltrexone may decrease the excretion rate of Pomalidomide which could result in a higher serum level. |
| Potassium | Potassium may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Potassium acetate | Methylnaltrexone may decrease the excretion rate of Potassium acetate which could result in a higher serum level. |
| Potassium bic | Methylnaltrexone may decrease the excretion rate of Potassium bicarbonate which could result in a higher serum level. |
| Potassium cation | Potassium cation may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Potassium chloride | Potassium chloride may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Potassium citrate | Potassium citrate may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Potassium nitrate | Methylnaltrexone may decrease the excretion rate of Potassium nitrate which could result in a higher serum level. |
| Potassium perchlorate | Methylnaltrexone may decrease the excretion rate of Potassium perchlorate which could result in a higher serum level. |
| Potassium sulfate | Methylnaltrexone may decrease the excretion rate of Potassium sulfate which could result in a higher serum level. |
| Pralatrexate | Methylnaltrexone may decrease the excretion rate of Pralatrexate which could result in a higher serum level. |
| Pralidoxime | Pralidoxime may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pramipexole | Pramipexole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Prasugrel | Prasugrel may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Prednisone | Prednisone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pregabalin | Pregabalin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Probenecid | Probenecid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Procainamide | Methylnaltrexone may decrease the excretion rate of Procainamide which could result in a higher serum level. |
| Procaine benzylp | Methylnaltrexone may decrease the excretion rate of Procaine benzylpenicillin which could result in a higher serum level. |
| Promethazine | Promethazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Propantheline | Propantheline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Propiverine | Methylnaltrexone may decrease the excretion rate of Propiverine which could result in a higher serum level. |
| Propranolol | Propranolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Prucalopride | Prucalopride may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pyrantel | Methylnaltrexone may decrease the excretion rate of Pyrantel which could result in a higher serum level. |
| Pyrazinamide | Pyrazinamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Pyridoxine | Pyridoxine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Quetiapine | Quetiapine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Quinethazone | Quinethazone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Quinidine | Methylnaltrexone may decrease the excretion rate of Quinidine which could result in a higher serum level. |
| Rabeprazole | Rabeprazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ramelteon | Ramelteon may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ranitidine | Ranitidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ranolazine | Ranolazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Rasagiline | Rasagiline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Remifentanil | The therapeutic efficacy of Remifentanil can be decreased when used in combination with Methylnaltrexone. |
| Reserpine | Reserpine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Resorcinol | Methylnaltrexone may decrease the excretion rate of Resorcinol which could result in a higher serum level. |
| Ribavirin | Ribavirin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ribostamycin | Methylnaltrexone may decrease the excretion rate of Ribostamycin which could result in a higher serum level. |
| Rivaroxaban | Rivaroxaban may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Rizatriptan | Rizatriptan may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Rofecoxib | Rofecoxib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Roflumilast | Roflumilast may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ropivacaine | Ropivacaine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Rosiglitazone | Rosiglitazone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ruxolitinib | Methylnaltrexone may decrease the excretion rate of Ruxolitinib which could result in a higher serum level. |
| Sacubitril | Methylnaltrexone may decrease the excretion rate of Sacubitril which could result in a higher serum level. |
| Salbutamol | Salbutamol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Salicylamide | Salicylamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Salicylic acid | Salicylic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Salmon calcitonin | Salmon calcitonin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Salsalate | Salsalate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Samidorphan | Samidorphan may increase the opioid antagonism activities of Methylnaltrexone. |
| Saxagliptin | Saxagliptin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Secobarbital | Secobarbital may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Selenious acid | Methylnaltrexone may decrease the excretion rate of Selenious acid which could result in a higher serum level. |
| Selenium | Methylnaltrexone may decrease the excretion rate of Selenium which could result in a higher serum level. |
| Sibutramine | Sibutramine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sitagliptin | Sitagliptin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sodium acetate | Methylnaltrexone may decrease the excretion rate of Sodium acetate which could result in a higher serum level. |
| Sodium aurothi | Methylnaltrexone may decrease the excretion rate of Sodium aurothiomalate which could result in a higher serum level. |
| Sodium fluoride | Methylnaltrexone may decrease the excretion rate of Sodium fluoride which could result in a higher serum level. |
| Sodium sulfate | Methylnaltrexone may decrease the excretion rate of Sodium sulfate which could result in a higher serum level. |
| Sofosbuvir | Methylnaltrexone may decrease the excretion rate of Sofosbuvir which could result in a higher serum level. |
| Solriamfetol | Methylnaltrexone may decrease the excretion rate of Solriamfetol which could result in a higher serum level. |
| Sorafenib | Sorafenib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sorbitol | Sorbitol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Spironolactone | Spironolactone may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Stiripentol | Methylnaltrexone may decrease the excretion rate of Stiripentol which could result in a higher serum level. |
| Streptomycin | Methylnaltrexone may decrease the excretion rate of Streptomycin which could result in a higher serum level. |
| Strontium chloride | Methylnaltrexone may decrease the excretion rate of Strontium chloride which could result in a higher serum level. |
| Sucralfate | Sucralfate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sufentanil | The therapeutic efficacy of Sufentanil can be decreased when used in combination with Methylnaltrexone. |
| Sulbactam | Methylnaltrexone may decrease the excretion rate of Sulbactam which could result in a higher serum level. |
| Sulfadiazine | Sulfadiazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sulfamethoxazole | Sulfamethoxazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sulfasalazine | Sulfasalazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sulindac | Sulindac may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Sumatriptan | Sumatriptan may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| S Estrogens, A | Methylnaltrexone may decrease the excretion rate of Synthetic Conjugated Estrogens, A which could result in a higher serum level. |
| S Estrogens, B | Methylnaltrexone may decrease the excretion rate of Synthetic Conjugated Estrogens, B which could result in a higher serum level. |
| Tacrolimus | Tacrolimus may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tadalafil | Tadalafil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tamsulosin | Tamsulosin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tapentadol | The therapeutic efficacy of Tapentadol can be decreased when used in combination with Methylnaltrexone. |
| Tasimelteon | Methylnaltrexone may decrease the excretion rate of Tasimelteon which could result in a higher serum level. |
| Technetium Tc-99m | Methylnaltrexone may decrease the excretion rate of Technetium Tc-99m exametazime which could result in a higher serum level. |
| T mebrofenin | Methylnaltrexone may decrease the excretion rate of Technetium Tc-99m mebrofenin which could result in a higher serum level. |
| Techn oxidronate | Methylnaltrexone may decrease the excretion rate of Technetium Tc-99m oxidronate which could result in a higher serum level. |
| Tech pyrophosphate | Methylnaltrexone may decrease the excretion rate of Technetium Tc-99m pyrophosphate which could result in a higher serum level. |
| Teduglutide | Methylnaltrexone may decrease the excretion rate of Teduglutide which could result in a higher serum level. |
| Tegafur | Methylnaltrexone may decrease the excretion rate of Tegafur which could result in a higher serum level. |
| Telavancin | Telavancin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Temazepam | Temazepam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Temozolomide | Temozolomide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tenofovir alafenamide | The serum concentration of Tenofovir alafenamide can be increased when it is combined with Methylnaltrexone. |
| Tenofovir disoproxil | Tenofovir disoproxil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tenoxicam | Tenoxicam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Terbutaline | Terbutaline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Testolactone | Testolactone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Testosterone | Testosterone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Testosterone cypi | Methylnaltrexone may decrease the excretion rate of Testosterone cypionate which could result in a higher serum level. |
| Testosterone en | Methylnaltrexone may decrease the excretion rate of Testosterone enanthate which could result in a higher serum level. |
| Testosterone prop | Testosterone propionate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Testosterone undec | Methylnaltrexone may decrease the excretion rate of Testosterone undecanoate which could result in a higher serum level. |
| Tetracycline | Tetracycline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tetradecyl hydrogen | Methylnaltrexone may decrease the excretion rate of Tetradecyl hydrogen sulfate (ester) which could result in a higher serum level. |
| Thiabendazole | Thiabendazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Thiethylperazine | Thiethylperazine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tiaprofenic acid | Tiaprofenic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Ticlopidine | Ticlopidine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tiludronic acid | Tiludronic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Timolol | Timolol may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tinidazole | Tinidazole may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tiopronin | Methylnaltrexone may decrease the excretion rate of Tiopronin which could result in a higher serum level. |
| Tiotropium | Tiotropium may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tirofiban | Tirofiban may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tixocortol | Methylnaltrexone may decrease the excretion rate of Tixocortol which could result in a higher serum level. |
| Tobramycin | Methylnaltrexone may decrease the excretion rate of Tobramycin which could result in a higher serum level. |
| Tocopherol | Methylnaltrexone may decrease the excretion rate of Tocopherol which could result in a higher serum level. |
| Tolazamide | Tolazamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tolbutamide | Tolbutamide may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tolcapone | Tolcapone may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tolfenamic acid | Tolfenamic acid may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tolmetin | Tolmetin may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tolterodine | Tolterodine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tolvaptan | Tolvaptan may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Topiramate | Topiramate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Topotecan | Topotecan may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Torasemide | Torasemide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Tositumomab | Tositumomab may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tramadol | The therapeutic efficacy of Tramadol can be decreased when used in combination with Methylnaltrexone. |
| Trametinib | Methylnaltrexone may decrease the excretion rate of Trametinib which could result in a higher serum level. |
| Triamterene | Triamterene may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Triazolam | Triazolam may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Trichlormethiazide | Trichlormethiazide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
| Triethylenetetramine | Methylnaltrexone may decrease the excretion rate of Triethylenetetramine which could result in a higher serum level. |
| Trifluridine | Trifluridine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Trimebutine | Methylnaltrexone may decrease the excretion rate of Trimebutine which could result in a higher serum level. |
| Trimethoprim | Trimethoprim may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Trimetrexate | Trimetrexate may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Tropisetron | Methylnaltrexone may decrease the excretion rate of Tropisetron which could result in a higher serum level. |
| Vaborbactam | Methylnaltrexone may decrease the excretion rate of Vaborbactam which could result in a higher serum level. |
| Valaciclovir | Valaciclovir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Valbenazine | Methylnaltrexone may decrease the excretion rate of Valbenazine which could result in a higher serum level. |
| Valdecoxib | Valdecoxib may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Valganciclovir | Valganciclovir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Vancomycin | Methylnaltrexone may decrease the excretion rate of Vancomycin which could result in a higher serum level. |
| Varenicline | Varenicline may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Venlafaxine | Venlafaxine may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Verapamil | Verapamil may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Vilanterol | Methylnaltrexone may decrease the excretion rate of Vilanterol which could result in a higher serum level. |
| Viloxazine | Methylnaltrexone may decrease the excretion rate of Viloxazine which could result in a higher serum level. |
| Vortioxetine | Methylnaltrexone may decrease the excretion rate of Vortioxetine which could result in a higher serum level. |
| Warfarin | Methylnaltrexone may decrease the excretion rate of Warfarin which could result in a higher serum level. |
| Zaleplon | Zaleplon may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Zanamivir | Zanamivir may decrease the excretion rate of Methylnaltrexone which could result in a higher serum level. |
| Zonisamide | Zonisamide may increase the excretion rate of Methylnaltrexone which could result in a lower serum level and potentially a reduction in efficacy. |
Pregnancy and Lactation
AU TGA pregnancy category: B1
US FDA pregnancy category: C
Pregnancy
The limited available data with RELISTOR in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriages. There are clinical considerations when RELISTOR is used by pregnant women. In animal reproduction studies, no effects on embryofetal development were observed with the administration of intravenous methylnaltrexone bromide during organogenesis in rats and rabbits at doses up to 20 times and 26 times, respectively, the subcutaneous maximum recommended human dose (MRHD) of 12 mg RELISTOR injection per day. The intravenous doses in rats and rabbits are about 0.5 times and 0.7 times, respectively, an oral MRHD of 450 mg/day. Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Lactation
No information is available on the use of methylnaltrexone during breastfeeding. The manufacturer recommends against breastfeeding in mothers taking methylnaltrexone. Based on pharmacokinetic data, the oral absorption of methylnaltrexone appears to be very low. Observe breastfed infants who have been exposed to opioids during pregnancy or postpartum for signs of opioid withdrawal, especially diarrhea.
How should this medicine be used?
Methylnaltrexone comes as a tablet to take by mouth. It is usually taken once a day with water, at least 30 minutes before the first meal of the day. Take methylnaltrexone at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take methylnaltrexone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Methylnaltrexone is to be taken by people who are taking opioid (narcotic) medications. Talk to your doctor if you change how much or how often you take your opioid medication. If you stop taking opioid medications, you should stop taking methylnaltrexone as well.
You should stop taking other laxative medications when you start taking methylnaltrexone. However, be sure to let your doctor know if methylnaltrexone does not work for you after taking it for 3 days. Your doctor may tell you to take other laxative medication(s).
Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with methylnaltrexone and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) to obtain the Medication Guide.
Other uses for this medicine
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What special precautions should I follow?
Before taking methylnaltrexone,
- tell your doctor and pharmacist if you are allergic to methylnaltrexone, any other medications, or any of the ingredients in methylnaltrexone tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: alvimopan (Entereg), naldemedine (Symproic), naloxegol (Movantik), naloxone (Evzio, Narcan, in Bunavail, Suboxone, Zubsolv), or naltrexone (Vivitrol, in Contrave, Embeda). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had a gastrointestinal obstruction (a blockage in your bowel). Your doctor will probably tell you not to take methylnaltrexone.
- tell your doctor if you have or have ever had stomach or bowel problems including stomach ulcer (sores in the lining of the stomach), cancer of the stomach or bowel, Crohn’s disease (a condition in which the body attacks the lining of the digestive tract, causing pain, diarrhea, weight loss, and fever), diverticulitis (small pouches in the lining of the large intestine that can become inflamed), Ogilvie’s syndrome (a condition in which there is a bulge in the bowel), or kidney or liver disease.
- tell your doctor if you are pregnant or plan to become pregnant. If you become pregnant while taking methylnaltrexone, call your doctor. If you take methylnaltrexone during your pregnancy, your baby may experience opioid withdrawal symptoms.
- tell your doctor if you are breastfeeding. Do not breastfeed while you are taking methylnaltrexone.
- you should know that most people have a bowel movement within a few minutes to a few hours after taking methylnaltrexone. Make sure that you are close to a bathroom when you take this medication.
