Non-Dihydropyridine Calcium Channel Blocker Pregnancy: Should not be given during the first trimester unless essential in the clinician's judgement (animal studies show no teratogenic effects). Excreted into breast milk in small amounts and unlikely to be harmful; use during lactation only if essential.

Verapamil

Brand names: Securon, Univer

Used in: Atrial Fibrillation

Verapamil is a rate-limiting (non-dihydropyridine) calcium-channel blocker used for angina, hypertension and certain supraventricular arrhythmias.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Hypertension: initially 120 mg twice daily, increasing to 160 mg twice daily when necessary; in some cases up to 480 mg daily in divided doses

Route: Oral (oral solution)

Frequency: twice daily (b.d.) for hypertension; three times daily (t.d.s.) for angina and supraventricular tachycardias

Max: 480 mg daily (in divided doses)

Angina: 120 mg three times daily recommended (80 mg three times daily can be satisfactory in some patients with angina of effort; less than 120 mg three times daily is not likely to be effective in variant angina). Supraventricular tachycardias: 40-120 mg three times daily according to severity. Hepatic impairment: reduce and carefully titrate the dose (verapamil is extensively metabolised in the liver). Renal impairment: prescribe cautiously with careful patient monitoring (about 70% excreted as metabolites in urine); not removed by dialysis. Elderly: adult dose recommended unless liver or renal function is impaired. Paediatric statement in this SPC (not a per-kg dose; verify against a children's formulary): up to 2 years 20 mg 2-3 times a day; 2 years and above 40-120 mg 2-3 times a day, according to age and effectiveness.

Dose adjustments

Renal

Prescribe cautiously with careful patient monitoring in renal impairment (pharmacokinetics not affected, but caution advised); verapamil is not removed during dialysis.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION The dose of verapamil must be individualized by titration. The usefulness and safety of dosages exceeding 480 mg/day have not been established; therefore, this daily dosage should not be exceeded. Since the half-life of verapamil increases during chronic dosing, maximum response may be delayed. Angina: Clinical trials show that the usual dose is 80 mg to 120 mg three times a day. However, 40 mg three times a day may be warranted in patients who may have an increased response to verapamil (e.g., decreased hepatic function, elderly, etc.). Upward titration should be based on therapeutic efficacy and safety evaluated approximately eight hours after dosing. Dosage may …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-05-22. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to verapamil or any excipient
Cardiogenic shock
Acute myocardial infarction complicated by bradycardia, marked hypotension or left ventricular failure
Second or third degree AV block (except with a functioning artificial pacemaker)
Sino-atrial block; sick sinus syndrome (except with a functioning artificial pacemaker)
Uncompensated heart failure
Bradycardia of less than 50 beats/minute; hypotension of less than 90 mmHg systolic
Atrial flutter or fibrillation associated with an accessory pathway (e.g. WPW, Lown-Ganong-Levine syndrome)
Porphyria
Intravenous dantrolene; combination with ivabradine; concomitant grapefruit juice

Side effects

Constipation
Headache and dizziness
Bradycardic arrhythmias (sinus bradycardia, AV block), development or aggravation of heart failure
Peripheral oedema and hypotension
Nausea; flushing

Interactions

Ivabradine (combination contraindicated)
Intravenous dantrolene (contraindicated)
HMG-CoA reductase inhibitors (simvastatin, atorvastatin, lovastatin) - start at lowest possible verapamil dose and titrate up
Beta-blockers (see precautions)
Grapefruit juice (may increase verapamil plasma levels)

Clinical monograph

How it works

It blocks L-type calcium channels, slowing conduction through the atrioventricular node, reducing heart rate and contractility, and causing vasodilatation.

Prescribing in practice

Do not combine with a beta-blocker because of the risk of severe bradycardia, heart block and asystole.
It is contraindicated in significant left ventricular dysfunction and heart failure as it is strongly negatively inotropic.
It raises plasma digoxin levels and commonly causes constipation.

Monitoring

Monitor heart rate, blood pressure and for signs of heart failure; review concurrent digoxin and other rate-limiting drugs.

Counselling the patient

Report a slow pulse, dizziness, fainting or breathlessness.
Constipation is common — maintain fluids and fibre, and seek advice if troublesome.

Evidence & guidelines

A long-established treatment for angina, hypertension and rate control in supraventricular arrhythmias in UK practice.

Reference: ESC AF Guidelines 2020; ACC/AHA Guideline on Atrial Fibrillation; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Same class

Pathways

Calcium channel blocker overdoseRecommended
TOXBASE/NPIS; AACT/EAPCCT; ESC

Same specialty