What is Verapamil used for?

Verapamil is evaluated for the following indications with varying evidence strength: Non-valvular atrial fibrillation (evidence tier A), Vasospastic (Prinzmetal) angina (evidence tier A), Migraine prophylaxis (evidence tier B). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Verapamil?

Common side effects of Verapamil (≥ 1 in 100): Constipation (most frequent adverse event, up to 25 percent of patients), Bradycardia, PR-interval prolongation, Dizziness, Peripheral edema, Facial flushing, headache. See the Safety section for uncommon and serious reactions.

Who should not take Verapamil?

Verapamil is contraindicated in: Systolic heart failure (LVEF below 40 percent); Second- and third-degree AV block without a pacemaker; Sick sinus syndrome without a pacemaker; WPW syndrome with atrial fibrillation; Cardiogenic shock. Full list in the Safety section.

Verapamil controls ventricular rate in atrial fibrillation and terminates paroxysmal supraventricular tachycardias in patients with preserved left ventricular systolic function. 2024 lists non-dihydropyridine calcium channel blockers as first-line rate control in AF without heart failure or AV block. Alternative to beta-blockers, especially with co-existing asthma.

Contraindicated with LVEF below 40 percent because of acute decompensation risk. Not combined with beta-blockers because of complete AV block and asystole risk.

Vasospastic (Prinzmetal) angina

First line

Vasospastic Prinzmetal angina responds to non-dihydropyridine and dihydropyridine calcium channel blockers. Verapamil reduces the frequency of coronary spasm and nitrate use in long-term therapy. 2023 lists CCBs as first-line therapy combined with long-acting nitrates. Beta-blockers are contraindicated in vasospastic angina because they intensify spasm.

Sources

Hypertrophic cardiomyopathy

First line

In obstructive hypertrophic cardiomyopathy verapamil reduces the LV outflow tract gradient and improves exercise tolerance. / 2024 recommends verapamil or beta-blockers as first-line therapy in patients with symptomatic obstruction. Verapamil is avoided in severe obstruction with a resting gradient above 100 mm Hg or systolic BP below 100 mm Hg because of severe hypotension and pulmonary edema risk.

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Migraine prophylaxis

Second line

Verapamil is considered second-line for migraine prevention, particularly with co-existing hypertension. 2019 classifies it as level U (insufficient evidence) for classic migraine and level C for cluster headache at 240–480 mg daily. Off-label in the Russian Federation, with individual dosing under PR-interval monitoring on ECG.

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Hypertension

Not recommended

Verapamil lowers blood pressure but is not selected as first-line monotherapy for essential hypertension. 2024 and NG136 prefer amlodipine, a dihydropyridine, for BP control: a milder side-effect profile and no risk of bradycardia or AV block. Verapamil is used when concurrent rate control is needed or with co-existing angina or vasospasm.

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Timing and administration

Immediate-release formulations are taken 3 times daily with food; food slows absorption and lessens flushing. Extended-release (Isoptin SR 240, Verelan) is taken once daily in the morning. Do not crush or chew the tablet: rate and BP control may be lost.

Dose titration

AF rate-control start dose is 40–80 mg three times daily or 240 mg extended-release once daily. Titrate every 1–2 weeks to a resting heart rate of 60–80 bpm. Maximum 480 mg daily. In patients over 75 and in hepatic impairment the dose is halved.

Monitoring

An ECG is taken before initiation to rule out second- or third-degree AV block and WPW with AF. Repeat at 1–2 weeks to assess PR interval. In patients with heart failure, EF assessment before starting is mandatory. Monitor ALT if jaundice, fatigue, or right-upper-quadrant pain appears.

Special situations

Grapefruit and grapefruit juice inhibit CYP3A4 and raise verapamil concentrations 1.5- to 2-fold: patients are advised to avoid them. Verapamil itself raises digoxin levels by 50–75 percent and simvastatin levels 2- to 4-fold (maximum simvastatin dose with verapamil is 20 mg/day). Constipation is managed with fiber, hydration, and osmotic laxatives if needed.

Common myths

Myth: “verapamil can be combined with beta-blockers to potentiate the rate-slowing effect”. Fact: the combination is forbidden in cardiology – additive sinus and AV node suppression can produce complete block and asystole.

Myth: “extended-release tablets can be split if the dose feels too high”. Fact: splitting destroys the release matrix and delivers the full dose at once with severe bradycardia risk. Adjust dose by switching to a different strength, not by splitting.

Myth: “non-dihydropyridine CCBs do not cause edema”. Fact: verapamil causes peripheral edema less often than amlodipine, but in 5–10 percent of patients it appears, driven by precapillary vasodilation rather than fluid retention.

Grapefruit

Grapefruit and grapefruit juice inhibit intestinal CYP3A4 and increase verapamil plasma concentrations 1.5- to 2-fold. The hypotensive and bradycardic effects intensify, with increased AV-block risk. Patients are advised to avoid grapefruit and grapefruit juice throughout verapamil therapy.

Source: FDA: Calan (verapamil hydrochloride) tablets – Prescribing Information (2023)

Major

Amiodarone

Class III antiarrhythmics (Vaughan Williams)

Mechanism

Additive suppression of sinus node and atrioventricular (AV) conduction. Symptomatic bradycardia, sinoatrial and AV block have been reported.

Symptoms

Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block. Older patients: fall risk.

Management

Avoid the combination. In atrial fibrillation, choose one strategy: amiodarone for rhythm control, verapamil for rate control. Alternatives: a beta-blocker + digoxin or catheter ablation.

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Mechanism of action

Indications

Practical notes

Timing and administration

Dose titration

Monitoring

Special situations

Common myths

Drug–nutrient interactions

Grapefruit

Drug–drug interactions

Check interaction with another drug

Official sources

Safety

Contraindications

Serious adverse effects

Common adverse effects

Uncommon adverse effects

PregnancyFDA C

Frequently asked