Carbamazepine; Uses, Dosage, Side Effects, Drug Interactions

An anticonvulsant used to control grand mal and psychomotor or focal seizures. Its mode of action is not fully understood, but some of its actions resemble those of phenytoin; although there is a little chemical resemblance between the two compounds, their three-dimensional structure is similar. It is not effective for absence seizures or myoclonic seizures. It is used in schizophrenia along with other medications and as a second line agent in bipolar disorder. Carbamazepine appears to work as well as phenytoin and valproate.

Mechanism of action of Carbamazepine

Carbamazepine inhibits sustained repetitive firing by blocking use-dependent sodium channels. Pain? relief is believed to be associated with blockade of synaptic transmission in the trigeminal nucleus and seizure? control with a reduction of post-tetanic potentiation of synaptic transmission in the spinal cord. Carbamazepine also possesses anticholinergic, central antidiuretic, antiarrhythmic, muscle relaxant, antidepressant (possibly through blockade of norepinephrine release), sedative, and neuromuscular-blocking properties.

Indications Carbamazepine 

• Trigeminal neuralgia.
• Acute? mania
• Grand mal generalized tonic-clonic seizure
• Mixed manic depressive episode
• Restless legs syndrome 
• Partial onset seizure Epilepsy
• Bipolar disorder
• Borderline personality disorder
• Epilepsy
• Schizoaffective disorder
• Cyclothymic disorder
• Diabetic peripheral neuropathy
• Dystonia
• Occipital neuralgia
• Peripheral neuropathy
• Reflex sympathetic dystrophy syndrome
• Vulvodynia

Therapeutic Indications of Carbamazepine

• Analgesics, Non-Narcotic; Anticonvulsants
• Carbamazepine has been shown to be effective in certain psychiatric disorders including schizoaffective illness, resistant schizophrenia, and dyscontrol syndrome, associated with limbic system dysfunction.
• Carbamazepine is used for the detoxification of alcoholics. It has been found to be effective in rapidly relieving anxiety and distress of acute? alcohol withdrawal and for such symptoms as seizures, hyperexcitability, and sleep disturbances.
• Carbamazepine is used alone or with other agents such as clofibrate or chlorpropamide in the treatment of partial central insulin? is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes? insipidus
• Carbamazepine is used alone or in combination with lithium and/or antidepressants or antipsychotics to treat patients with manic-depressive illness who are unresponsive to or cannot tolerate, lithium or neuroleptics alone.
• Carbamazepine may also be used in some patients to relieve the lightning pains of tabes dorsalis; neuralgic pain? associated with multiple sclerosis?, acute? idiopathic? neuritis (Guillain-Barre syndrome), peripheral diabetic numbness?, tingling, or weakness?. সহজ বাংলা: স্নায়ুর ক্ষতি/সমস্যা।" data-rx-term="neuropathy" data-rx-definition="Neuropathy means nerve damage or irritation causing pain, numbness, tingling, or weakness. সহজ বাংলা: স্নায়ুর ক্ষতি/সমস্যা।">neuropathy?, phantom limb, restless leg syndrome (Ekbom’s syndrome), and hemifacial spasm?; post-traumatic neuropathy or neuralgia; and postherpetic neuralgia.
• Carbamazepine is indicated for the relief of pain? due to true trigeminal neuralgia (tic douloureux) and glossopharyngeal neuralgia.
• Carbamazepine is indicated for the treatment of partial seizures with simple or complex symptomatology (psychomotor, temporal lobe); generalized tonic-clonic seizures (grand mal); mixed seizure? patterns that include the above; or other partial or generalized seizures. Carbamazepine is a first-choice anticonvulsant because of its relatively low behavioral and psychological toxicity and the rarity of serious adverse effects.
• Benign? infantile convulsions are characterized by (1) onset at up to 2 years of age, (2) normal development, (3) mostly brief, often clustered convulsions, and (4) normal electroencephalography during the interictal stage. BIC follow a favorable course and disappear before 2-3 years of age, although convulsions for which diazepam is ineffective frequently develop.

Contra-Indications of Carbamazepine

• Syndrome of inappropriate antidiuretic hormone secretion
• High cholesterol
• Low amount of sodium in the blood
• Hepatic porphyria
• Decreased function of bone marrow
• Low blood counts due to bone marrow failure
• Decreased blood platelets
• Deficiency of Granulocytes a type of white blood cell
• Mood changes
• Having thoughts of suicide
• Depression
• Myasthenia gravis
• Increased pressure in the eye
• Increased pressure in eyes
• high blood pressure
• Coronary artery disease
• Complete heart block
• abnormal heart rhythm
• Chronic heart failure
• Liver problems
• Kidney disease with a reduction in kidney function
• Cannot empty bladder
• Pregnancy
• Poisoning by seizure? medication carbamazepine

Dosages of Carbamazepine

Strengths: 100 mg;  200 mg; 400 mg; 300 mg;100 mg/5 mL;

The amount of medicine that you take depends on the strength of the medicine.

 Bipolar disorder

• Adults—At first, 200 milligrams (mg) two times a day. Your doctor may increase your dose as needed. However, the dose is usually not more than 1600 mg per day.
• Children—Use and dose must be determined by your doctor.

Epilepsy

• Adults and children 12 years of age and older—At first, 200 milligrams (mg) two times a day. Your doctor may increase your dose as needed. However, the dose is usually not more than 500 to 800 mg two times a day.
• Children younger than 12 years of age—Dose is based on body weight and must be determined by your doctor. However, the dose is usually not more than 1000 mg per day.

Trigeminal neuralgia

• Adults—At first, 200 milligrams (mg) once a day. Your doctor may increase your dose as needed and tolerated. However, the dose is usually not more than 1200 mg per day.
• Children—Use and dose must be determined by your doctor.
• For oral dosage? form (extended-release tablets)

For Epilepsy

• Adults—At first, 200 mg two times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 1000 to 1600 mg per day.
• Children 6 to 12 years of age—At first, 100 mg two times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 1000 mg per day.
• Children younger than 6 years of age—Use and dose must be determined by your doctor.

For trigeminal neuralgia

• Adults—At first, 100 milligrams (mg) two times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 1200 mg per day.
• Children—Use and dose must be determined by your doctor
• For oral dosage? form (suspension):

For epilepsy

• Adults—100 milligrams (mg) or 1 teaspoon four times a day (400 mg per day). Your doctor may adjust your dose if needed. However, the dose is usually not more than 1000 to 1600 mg per day.
• Children 6 to 12 years of age—At first, 50 milligrams (mg) or one-half teaspoon four times a day (200 mg per day). Your doctor may adjust your dose if needed. However, the dose is usually not more than 1000 mg per day.
• Children younger than 6 years of age—Dose is based on body weight and will be determined by your doctor. The dose is 10 to 20 milligrams (mg) per kilogram (kg) of body weight per day, taken four times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 35 mg per kg of body weight per day.

For trigeminal neuralgia

• Adults—At first, 50 milligrams (mg) or one-half teaspoon four times a day (200 mg per day). Your doctor may adjust your dose if needed. However, the dose is usually not more than 1200 mg per day.
• Children—Use and dose must be determined by your doctor.

For oral dosage? forms (tablets or chewable tablets)

For epilepsy

• Adults—At first, 200 milligrams (mg) two times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 1000 to 1600 mg per day.
• Children 6 to 12 years of age—At first, 100 mg two times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 1000 mg per day.
• Children younger than 6 years of age—Dose is based on body weight and will be determined by your doctor. The dose is 10 to 20 milligrams (mg) per kilogram (kg) of body weight per day, taken two or three times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 35 mg per kg of body weight per day.

For trigeminal neuralgia

• Adults and teenagers—At first, 100 milligrams (mg) two times a day. Your doctor may adjust your dose if needed. However, the dose is usually not more than 1200 mg per day.
• Children—Use and dose must be determined by your doctor.

Side Effects of Carbamazepine 

The most common

• Nausea and vomiting
• Severe stomach ache
• epigastric pain
• diarrhea,
• anorexia,
• flatulence,
• a headache,
• dizziness,
• fainting, fast or pounding heartbeats;
• confusion, hallucinations;

 Common

• Nausea and vomiting
• Severe stomach ache
• Severe diarrhea
• Mouth sores
• Vaginal thrush
• Skin rash?
• A headache
• Ringing or buzzing in the ears
• Decreased appetite

Rare

• Body aches or pain
• a cough
• difficulty having a bowel movement (stool)
• dry mouth
• ear congestion
• frequent urination
• a headache
• lack or loss of strength
• loss of appetite
• loss of voice
• muscle aches
• nausea
• sleepiness or unusual drowsiness
• a sore throat
• stuffy or a runny nose
• sweating increased
• trouble sleeping
• weight loss
• lack of appetite
• loss of balance control
• loss of interest or pleasure
• muscle trembling, jerking, or stiffness

Drug Interactions of Carbamazepine

Carbamazepine may interact with following drugs, supplements & may decrease the efficacy of drugs

• alpha/beta agonists (e.g., epinephrine, norepinephrine)
• alpha blockers (e.g., alfuzosin, doxazosin, tamsulosin)
• alpha agonists (e.g., clonidine, methyldopa)
• angiotensin-converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
• angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
• anti-psychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzepine, quetiapine,risperidone)
• aripiprazole
• beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
• bupropion
• calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
• carbamazepine
• celecoxib
• clobazam
• clopidogrel
• diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
• glucosamine
• heparin
• lorazepam
• mirabegron
• mirtazapine
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, )
• multivitamins with minerals
• nitrates (e.g., nitroglycerin, isosorbide )
• nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., ibuprofen, naproxen, ketoprofen)
• phenobarbital
• quinolone antibiotics (e.g., ciprofloxacin, enoxacin, norfloxacin)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, duloxetine, fluoxetine, paroxetine, sertraline)
• serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine,venlafaxine)
• tapentadol
• tramadol
• tricyclic antidepressants (e.g., imipramine, amitriptyline, nortriptyline, desipramine)
• triptans (e.g., sumatriptan, rizatriptan)
• tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib)
• warfarin
• valproate,
• warfarin, z
• zonisamide.

Pregnancy & Lactation of Carbamazepine

FDA Pregnancy Category D 

Pregnancy

Offspring of epileptic mothers with untreated epilepsy are known to be more prone to developmental disorders, including malformations. Developmental disorders and malformations, including spina bifida, and also other congenital? anomalies e.g. craniofacial defects such as clept lip/palate, cardiovascular malformations, hypospadias and anomalies involving various body systems, have been reported in association with the use of Tegretol. Patients should be counselled regarding the possibility of an increased risk of malformations and given the opportunity of antenatal screening?

Lactation

Carbamazepine passes into the breast milk (about 25-60% of the plasma concentrations). The benefits of breast-feeding should be weighed against the remote possibility of adverse effects occurring in the infant. Mothers taking Tegretol may breast-feed their infants, provided the infant is observed for possible adverse reactions (e.g. excessive somnolence, allergic skin reaction). There have been some reports of cholestatic hepatitis? in neonates exposed to carbamazepine during antenatal and or during breast feeding. Therefore breast-fed infants of mothers treated with carbamazepine should be carefully observed for adverse hepatobiliary effects.

References