Non-dihydropyridine CCB Pregnancy: Should not be given during the first trimester unless essential in the clinician's judgement (animal studies show no teratogenic effects). Excreted in breast milk (infant relative dose 0.1-1% of the mother's oral dose); use during lactation only if essential for the welfare of the mother.

Verapamil hydrochloride

Brand names: Securon, Cordilox

Verapamil hydrochloride is a non-dihydropyridine (rate-limiting) calcium-channel blocker used for angina, hypertension, and supraventricular arrhythmias including rate control in atrial fibrillation.

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: 240 mg once daily (one Securon SR tablet); in patients new to verapamil consider starting at 120 mg (one Half Securon SR tablet)

Route: Oral (modified-release / SR tablets; swallow whole without sucking or chewing, preferably with or shortly after meals)

Frequency: once daily for hypertension; twice daily for angina

Max: 480 mg daily (two Securon SR tablets, one in the morning and one in the evening about twelve hours apart)

Hypertension: most patients respond to 240 mg daily as a single dose; if control is not achieved after at least one week, increase to a maximum of 480 mg daily. Angina pectoris: 240 mg twice daily; where indicated may be adjusted down to 240 mg once daily. Secondary prevention of reinfarction after an acute MI (patients without heart failure, not receiving diuretics, where beta-blockers are not appropriate): start at least one week after the acute MI - 360 mg/day in divided doses, either 120 mg three times daily, or 240 mg in the morning plus 120 mg in the evening. Elderly: adult dose recommended unless renal or hepatic function is impaired. Liver impairment: adjust dosage with special caution and give low doses initially (metabolism delayed). Children: Securon SR and Half Securon SR are not recommended for children. Half Securon SR (120 mg) may be used for dose titration.

Dose adjustments

Renal

Caution and careful patient monitoring in renal impairment (pharmacokinetics not affected); 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.

Contraindications

Hypersensitivity to the active substance 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/fibrillation in the presence of an accessory pathway (e.g. WPW syndrome)
Combination with ivabradine

Side effects

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

Interactions

Ivabradine (combination contraindicated)
Intravenous beta-adrenergic blocking agents or disopyramide (serious adverse effects reported, especially in severe cardiomyopathy, CHF or recent MI)
Agents that decrease adrenergic function (exaggerated hypotensive response)
HMG-CoA reductase inhibitors (simvastatin, atorvastatin, lovastatin) - start at lowest possible verapamil dose and titrate up
CYP3A4 (and CYP1A2, CYP2C8, CYP2C9, CYP2C18) inhibitors/inducers (verapamil is metabolised by these enzymes)

Clinical monograph

How it works

It blocks L-type calcium channels in cardiac and vascular smooth muscle, slowing atrioventricular nodal conduction and reducing heart rate, myocardial contractility and vascular tone.

Prescribing in practice

Verapamil is strongly negatively inotropic and chronotropic, so combining it with a beta-blocker risks severe bradycardia, heart block or hypotension, and this combination should generally be avoided.
It is contraindicated in significant left ventricular dysfunction or heart failure, high-grade AV block and certain accessory-pathway arrhythmias, and it should be avoided in ventricular tachycardia.
It inhibits CYP3A4 and raises levels of several drugs (including some statins and digoxin), and commonly causes constipation.

Monitoring

Monitor heart rate, blood pressure and the ECG (especially AV conduction) when initiating or adjusting therapy, and review for heart-failure symptoms.

Counselling the patient

Report marked dizziness, fainting, very slow pulse or swelling ankles.
Manage constipation with diet and fluids and seek advice if troublesome.
Tell prescribers you take verapamil before starting new medicines, as interactions are common.

Evidence & guidelines

Verapamil's role in rate control and angina is well established, and NICE recommends rate-limiting calcium-channel blockers among options for rate control in atrial fibrillation when beta-blockers are unsuitable.

Reference: NICE NG196; ESC; 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.

Pathways