API

Verapamil hydrochloride

Drug classification

Dosage form

Tablet

API strength per dosage

1 sustained-release tablet contains 240 mg…

Dose

Adults: 240 mg once daily, preferably in the morning. Pediatrics: Safety and efficacy not established. Elderly or hepatic impairment: Initiate at lower doses and titrate cautiously. Adjust dose based on clinical response and tolerability.

Mechanism of action

Inhibits L-type voltage-gated calcium channels (Cav1.2) in cardiac and vascular smooth muscle cells, reducing intracellular calcium influx, thereby decreasing myocardial contractility, heart rate (via sinoatrial and atrioventricular node suppression), and vascular tone, resulting in negative inotropic, chronotropic, and vasodilatory effects.

Indications

Essential hypertension, chronic stable angina pectoris, vasospastic (Prinzmetal’s) angina, supraventricular tachyarrhythmias including atrial fibrillation and atrial flutter with rapid ventricular response.

Side effects

Bradycardia, hypotension, heart block, heart failure exacerbation, dizziness, headache, constipation, nausea, peripheral edema, flushing, elevated liver enzymes.

Pregnancy category

Category C

Precautions

Contraindications

Severe hypotension, cardiogenic shock, second- or third-degree AV block (without pacemaker), sick sinus syndrome (without pacemaker), severe left ventricular dysfunction, atrial fibrillation/flutter with accessory pathway, hypersensitivity to verapamil.