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Verapamil is a phenylalkylamine calcium channel blocking agent. Verapamil inhibits the transmembrane influx of extracellular calcium ions into myocardial and vascular smooth muscle cells, causing dilatation of the main coronary and systemic arteries and decreasing myocardial contractility. This agent also inhibits the drug efflux pump P-glycoprotein which is overexpressed in some multi-drug resistant tumors and may improve the efficacy of some antineoplastic agents.
Verapamil is a first generation calcium channel blocker used for the treatment of hypertension, angina pectoris, and superventricular tachyarrhythmias. Verapamil has been linked to a low rate of serum enzyme elevations during therapy and too rare instances of clinically apparent acute liver injury.
Verapamil is a calcium channel blocker that is a class IV anti-arrhythmia agent. The drug is used for the treatment of high blood pressure, chest pain from not enough blood flow to the heart, and supraventricular tachycardia. It may also be used for the prevention of migraines and cluster headaches. It is given by mouth or by injection into a vein.
Mechanism of action of Verapamil
Verapamil inhibits voltage-dependent calcium channels. Specifically, its effect on L-type calcium channels in the heart causes a reduction in ionotropy and chronotropy, this is reducing heart rate and blood pressure. Verapamil’s mechanism of effect in a cluster pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।" data-rx-term="headache" data-rx-definition="Headache means pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।">headache is thought to be linked to its calcium-channel blocker effect, but which channel subtypes are involved is presently not known. Verapamil is an L-type calcium channel blocker that also has antiarrhythmic activity. The R-enantiomer is more effective at reducing blood pressure compared to the S-enantiomer. However, the S-enantiomer is 20 times more potent than the R-enantiomer at prolonging the PR interval in treating arrhythmias.
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Verapamil has been shown to be neuroprotective in several acute neurotoxicity models due to blockade of calcium entry into neurons. However, the potential use of verapamil to treat chronic neurodegenerative diseases has not been reported. Using rat primary mesencephalic neuron/glia cultures, we report that verapamil significantly inhibited LPS-induced dopaminergic neurotoxicity in both pre- and post-treatment experiments. Reconstituted culture studies revealed that the presence of microglia was essential in verapamil-elicited neuroprotection. Mechanistic studies showed that decreased production of inflammatory mediators from LPS-stimulated microglia underlay neuroprotective property of verapamil. Further studies demonstrated that microglial NADPH oxidase (PHOX), the key superoxide-producing enzyme, but not calcium channel in neurons, is the site of action for the neuroprotective effect of verapamil. This conclusion was supported by the following two observations: 1) Verapamil failed to show protective effect on LPS-induced dopaminergic neurotoxicity in PHOX-deficient (deficient in the catalytic subunit of gp91(phox)) neuron/glia cultures; 2) Ligand binding studies showed that the binding of (3)H-verapamil onto gp91(phox) transfected COS7 cell membranes was higher than the non-transfected control. The calcium channel-independent neuroprotective property of verapamil was further supported by the finding that R(+)-verapamil, a less active form in blocking calcium channel, showed the same potency in neuroprotection, inhibition of pro-inflammatory factors production and binding capacity to gp91(phox) membranes as R(-)-verapamil, the active isomer of calcium channel blocker. In conclusion, our results demonstrate a new indication of verapamil-mediated neuroprotection through a calcium channel-independent pathway and provide a valuable avenue for the development of therapy for infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation-related neurodegenerative diseases.
Indications of Verapamil
- Angina,
- Atrial Flutter
- High blood pressure (Hypertension)
- Hypertrophic cardiomyopathy
- Migraines
- Nonvalvular atrial fibrillation
- Paroxysmal supraventricular tachycardia
- Secondary prevention MI
- Unstable angina
- Chronic, stable angina pectoris
- Cluster headaches
- Arrhythmia
- High blood pressure
- Bipolar disorder
- Migraine prevention
- Angina
- Idiopathic hypertrophic subaortic Stenosis
- Nocturnal leg cramps
- Supraventricular tachycardia
Contra-Indications of Verapamil
- Myasthenia Gravis
- Weakened Communication Between Muscles and Nerves
- Duchenne muscular dystrophy
- Complete Heart Block
- Second Degree Atrioventricular Heart Block
- Wolff-Parkinson-white Syndrome
- Rapid ventricular heartbeat
- Sick Sinus Syndrome
- Slow heartbeat
- Severe heart failure
- Failure of the left ventricle of the heart
- The decrease in the Amount of Work the Heart Does
- Abnormally low blood pressure
- Severely Low Blood Pressure
- Liver problems
- Kidney disease with the reduction in kidney function
- Blood circulation failure due to a serious heart condition
- Abnormal liver function tests
- Chronic idiopathic constipation
- Lown-Ganong-Levine syndrome
- First-degree atrioventricular heart Block
- Hypersensitivity to the active substance or to any of the excipients
- Hypotension (of less than 90mmHg systolic)
- Second or third-degree atrioventricular block; sick sinus syndrome (except in patients with a functioning artificial pacemaker); uncompensated heart failure; marked bradycardia (less than 50 beats/minute).
- The combination with beta-blockers is contraindicated in patients with poor ventricular function.
- Wolff-Parkinson-White syndrome.
- Concomitant ingestion of grapefruit juice is contraindicated.
- Acute myocardial infarction complicated by bradycardia marked hypotension or left ventricular failure.
- Combination with ivabradine
Dosage of Verapamil
Strengths
- 2.5 mg/mL
Tablet
- 40 mg ;80 mg ;120 mg
Tablet/capsule, extended release
- 100 mg ;120 mg ;180 mg ;200 mg ;240 mg ;300 mg ;360 mg
Dosage Considerations
Angina
- Adult, Immediate release: 80 mg orally every 8 hours initially; usual range: 80-120 mg orally every 8 hours; not to exceed 480 mg/day
- Adult, Extended-release: Covera-HS: 180 mg/day orally at bedtime initially; maintenance: 180-540 mg/day orally at bedtime
- Geriatric, Immediate release: 80 mg orally every 8 hours initially; usual range: 80-120 mg orally every 8 hours; not to exceed 480 mg/day
- Geriatric, Extended-release (Covera-HS): 180 mg orally at bedtime initially; maintenance: 180-540 mg orally at bedtime
Hypertension
Adult, Immediate release: 80 mg orally every 8 hours initially; maintenance: 80-320 mg orally every 12 hours
Adult, Extended-release
- Calan, Isoptin SR: 180 mg/day orally given in morning (120 mg/day initially if patient elderly or of small stature); for desired response, may be increased to 240 mg/day, then to 360 mg/day (either 180 mg every 12 hours or 240 mg in morning and 120 mg in evening)
- Verelan: 180 mg/day orally (120 mg/day initially if patient elderly or of small stature); for a desired response, may be increased to 240 mg/day orally, then by 120 mg/day at weekly intervals; not to exceed 480 mg/day
- Verelan PM: 200 mg/day orally at bedtime (100 mg/day if patient elderly or of small stature); may be increased by 100 mg/day at weekly intervals as needed; not to exceed 400 mg/day
- Covera-HS: 180 mg/day orally at bedtime (120 mg/day initially if patient elderly or of small stature); for the desired response, may be increased to 240 mg/day, then by 120 mg/day at weekly intervals; not to exceed 480 mg/day
Geriatric
- Immediate release: 40 mg orally every 8 hours initially; maintenance: 80-320 mg orally every 12 hours
- Extended-release (Calan SR, Isoptin SR, Verelan): 120 mg/day orally given in the morning
- Extended-release (Covera-HS): 180 mg/day orally at bedtime
- Extended-release (Verelan PM): 100 mg/day orally at bedtime
Supraventricular Arrhythmia and Atrial Fibrillation/Flutter
- 2.5-5 mg intravenously (IV) over 2 minutes; 5-10 mg dose may be repeated after 15-30 minutes
- Alternatively, 0.075-0.15 mg/kg (not to exceed 10 mg) IV over 2 minutes; dose may be repeated once 30 minutes after the first dose
Chronic Atrial Fibrillation and Paroxysmal Supraventricular Tachycardia
- Treatment of chronic atrial fibrillation (rate control); prevention of paroxysmal supraventricular tachycardia
- Immediate release: 240-480 mg/day orally divided every 6-8 hours
Supraventricular Tachycardia, Pediatric
- Children 1-15 years old: 0.1-0.3 mg/kg (not to exceed 5 mg) intravenously (IV) over 2 minutes; second dose (not to exceed 10 mg) may be given after 30 minutes
- Alternatively (not well established), 4-8 mg/kg/day orally divided every 8 hours
Tardive Dyskinesia
- 40 mg orally every 8 hours; may be titrated to 120 mg every 8 hours
A pain, nausea, or light sensitivity. সহজ বাংলা: বারবার হওয়া বিশেষ ধরনের মাথাব্যথা।" data-rx-term="migraine" data-rx-definition="Migraine is a recurring headache disorder often with throbbing pain, nausea, or light sensitivity. সহজ বাংলা: বারবার হওয়া বিশেষ ধরনের মাথাব্যথা।">migraine (Off-label)
- Prophylaxis
- 160-320 mg orally every 6-8 hours
Dosing Modifications
- Renal impairment: Use with caution; monitor ECG; for Verelan PM, the manufacturer recommends 100 mg at bedtime initially; if CrCl less than 10 mL/min, reduce dose by 25-50%
- Hepatic impairment: In cirrhosis, reduce dose by 20-50% of normal for oral and intravenous (IV) administration
- Geriatric: In general, lower initial doses are warranted; doses should be adjusted on basis of clinical response
Side Effects of Verapamil
The most common
- A dry cough
- Dizziness and light-headedness due to low blood pressure
- Fatigue, especially in the early stages
- Mouth dryness in the early stages
- The most common (a burning feeling in the chest, behind the breastbone or gullet)
- Abdominal or stomach pain
- Constipation
- High blood pressure
- Nausea, vomiting,
- painful or swollen gums
- numbness or heavy feeling in the jaw
- dull, aching pain in the hip, groin, or thigh
- stomach pain,
- a headache,
- reversible hair loss or thinning, and
- fever.
Common
- chills or fever
- a headache, severe and throbbing
- joint or back pain
- muscle aching or cramping
- muscle pains or stiffness
- chest pressure or squeezing pain in the chest
- excessive sweating
- sudden drowsiness or need to sleep
- coughing up blood
- liver problems–nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes)
- decreased amount of urine
Rare
- Anxiety
- change in vision
- chest pain or tightness
- confusion
- a cough
- Agitation
- arm, back, or jaw pain
- blurred vision
- chest pain or discomfort
- convulsions
- extra heartbeats
- hallucinations
- a headache
- irritability
- lightheadedness
- cold and clammy skin
- fast and shallow breathing
- swelling of your feet, legs, or hands purple spot on your skin caused by internal bleeding
- fast or abnormal heart rate or palpitations
- loss of appetite
Drug Interactions of Verapamil
Verapamil may interact with following drugs, supplyments, & may change the efficacy of drugs
- allopurinol
- alpha agonists (e.g., clonidine, methyldopa)
- angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
- azathioprine
- beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
- calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
- cyclosporine
- diuretics (water pills; e.g., furosemide, , spironolactone, )
- “gliptin” diabetes medications (e.g., linagliptin, saxagliptin, sitagliptin)
- heparin
- insulin
- iron dextran
- monoamine oxidase inhibitors (MAOIs; e.g ,phenelzine, rasagiline, selegiline, )
- nitroglycerin
- nonsteroidal anti-inflammatory medications (NSAIDs; e.g., indomethacin, naproxen)
- oral diabetes medications (e.g., metformin, pioglitazone)
- pentoxyifylline
- phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
- rituximab
- tizanidine
- trimethoprim
Pregnancy & Lactation of Verapamil
FDA Pregnancy Category C
Pregnancy
Verapamil reaches the developing baby if it is taken during pregnancy. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Lactation
This medication passes into breast milk. If you are a breast-feeding mother and are taking verapamil, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. The safety and effectiveness of using this medication have not been established for children.
References
