Verapamil

Verapamil, sold under various trade names, is a medication used for the treatment of high blood pressure, chest pain from not enough blood flow to the heart, and supraventricular tachycardia.

Verapamil

Verapamil hydrochloride; Verapamil HCl; Manidon; Calcan hydrochloride

Calaptin, Celovera, Vasopten, Veramil, Vpl

2-(3,4-dimethoxyphenyl)-5-{[2-(3,4-dimethoxyphenyl)ethyl](methyl)amino}-2-(propan-2-yl)pentanenitrile

90% absorbed from GI tract, 90% protein binding.

Verapamil is an L-type calcium channel blocker that also has antiarrythmic activity. The R-enantiomer is more effective at reducing blood pressure compared to the S-enantiomer. Verapamil inhibits voltage-dependent calcium channels. It causes a reduction in chronotropy and ionotropy, this reducing heart rate and blood pressure.

The recommended dose range is 120-480 mg/day in 3-4 divided doses as PO.

For the treatment of hypertension, angina, and cluster headache prophylaxis.

Heart block and cardiac failure in patients with preexisting cardiac disease. Hepatotoxicity. Bradycardia, dizziness, CHF, MI, AV block, worsening fatigue, heart failure, transient asystole, alopecia, hypotension, pulmonary and peripheral oedema, nausea. Constipation, hypotension, headache, palpitation, nausea, flushing, rashes, hyperprolactinaemia, increased LFT and arthralgia.

• Increased cardiac depressant effects with amiodarone.
• Increased risk of QT prolongation with dofetilide, ranolazine, sertindole.
• Additive bradycardia with ivabradine.
• Increased risk of heart block with clonidine.
• Increased risk of acute hyperkalaemia and CV collapse with dantrolene.
• Increased risk of additive bradycardia, conduction disturbances and digoxin toxicity with digoxin.
• Increased cardiac depressant effects with β-blockers and flecainide.
• Increased risk of bradycardia and hypotension with remifentanil and sufentanil.
• St John's wort reduces the bioavailability of verapamil.
• Increased levels of both everolimus and verapamil on concurrent use.
• Verapamil increase blood alcohol levels.
• Grapefruit juice increases serum concentration of verapamil by 40%.
• Buspirone, carbamazepine, ciclosporin, doxorubicin, epirubicin, eplerenone, quinupristin/dalfopristin, quinidine, sirolimus, statins, tacrolimus levels may increase.
• Unpredictable interactions with lithium.
• Increased verapamil concentrations with protease inhibitors and cimetidine.
• Verapamil concentrations decreased with Rifabutin, sulfinpyrazone, rifampicin, phenobarbital and rifapentine.

• Patients with atrial flutter or atrial fibrillation and an accessory bypass tract (e.g., Wolff-Parkinson-White, Lown-Ganong-Levine syndromes). Severe bradycardia, severe left ventricular dysfunction, cardiogenic shock, uncompensated heart failure, hypotension (systolic pressure <90 mm Hg), porphyria.
•  2nd or 3rd degree AV block (unless pacemaker is fitted).

Store it at room temperature.

Molecular weight

454.6016

Molecular formula

C27H38N2O4

CAS number

52-53-9

Precautions

• Avoid sudden withdrawal.
• 1st degree AV block.
• Bradycardia or conduction disturbances.
• For IV admin, verapamil to be given slowly under continuous ECG and BP monitoring.
• Patients with decreased neuromuscular transmission, Hypertrophic cardiomyopathy
• Hepatic or renal impairment.
• Periodic monitoring of LFT during long-term therapy.
• Slower infusion rates (over >3 minutes) in elderly.
• Pregnancy and lactation.
• Infants and neonates, elderly.