From the Guidelines
Verapamil is classified as a calcium channel blocker, specifically a non-dihydropyridine calcium channel antagonist. It works by blocking L-type calcium channels in cardiac muscle and vascular smooth muscle, which prevents calcium from entering cells. This action results in decreased myocardial contractility, slowed cardiac conduction (particularly at the AV node), and vasodilation. Verapamil is further subclassified as a Class IV antiarrhythmic agent according to the Vaughan Williams classification system due to its effects on cardiac conduction. Therapeutically, verapamil is used to treat hypertension, angina pectoris, certain cardiac arrhythmias (particularly supraventricular tachycardias), and occasionally for migraine prophylaxis. The typical oral dosage ranges from 120-480 mg daily, often divided into multiple doses, while intravenous administration is used for acute management of certain arrhythmias. Verapamil differs from other calcium channel blockers like dihydropyridines (such as amlodipine) by having more pronounced effects on cardiac conduction and less selective vasodilatory effects, making its cardiac effects more prominent than its peripheral vascular effects.
Some key points to consider when using verapamil include:
- It should be used cautiously or avoided in patients with heart failure due to systolic dysfunction because of its negative inotropic effects 1.
- Verapamil is effective in controlling the ventricular rate in atrial fibrillation, but its short duration of action usually requires continuous intravenous infusion to maintain rate control 1.
- Direct comparisons of verapamil and diltiazem have demonstrated similar effectiveness, with preserved or improved exercise tolerance in most patients 1.
- Verapamil may be preferred for long-term use over beta blockers in patients with bronchospasm or chronic obstructive pulmonary disease 1.
According to the most recent and highest quality study, verapamil is a non-dihydropyridine calcium channel antagonist that is effective in treating certain cardiac arrhythmias and has a unique mechanism of action 1. Its classification and therapeutic uses are well established, and it remains a valuable option for the treatment of various cardiovascular conditions.
From the FDA Drug Label
Verapamil hydrochloride is a calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) Verapamil Hydrochloride Extended-Release Tablets, USP are calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) Verapamil hydrochloride is a calcium antagonist or slow-channel inhibitor
Verapamil Classification:
- Calcium Channel Blocker: Verapamil is classified as a calcium channel blocker, specifically a calcium ion influx inhibitor or slow-channel blocker.
- Pharmacological Class: It belongs to the class of calcium ion antagonists.
- Therapeutic Class: Verapamil is used to treat various conditions, including hypertension, angina, and arrhythmias 2, 2, 3
From the Research
Verapamil Classification
- Verapamil is a non-dihydropyridine calcium channel blocker (CCB) 4, 5, 6
- It is widely used in the treatment of hypertension, chronic stable angina, secondary prevention of reinfarction, paroxysmal supra-ventricular tachycardia and for rate control in atrial fibrillation/flutter 4
- Verapamil exerts favorable effects on glycemic control, proteinuric diabetic nephropathy, left ventricular diastolic dysfunction and sympathetic nervous system overactivity 4
- Calcium channel blockers can be divided into three groups: the dihydropyridines, the phenylalkylamines and the benzothiazepines, with verapamil belonging to the phenylalkylamines group 6
- Non-dihydropyridine calcium channel blockers, including verapamil, can be used for the treatment of proteinuria in diabetic and nondiabetic kidney disease 7
Comparison with Other Calcium Channel Blockers
- Verapamil is nearly equipotent in producing coronary vasodilatation and a negative dromotropic effect, although it is less potent in producing negative inotropy compared to other non-dihydropyridine calcium antagonists 5
- Verapamil, diltiazem and KB-944 are nearly equipotent in producing negative dromotropic and chronotropic effects 5
- There are significant differences between agents within the dihydropyridine group of calcium channel blockers, which translate to distinct differences in therapeutic profiles 8