verapamil hydrochloride: clinical use

Prescribing considerations

• Confirm the indication and formulation because licensed uses and release characteristics differ.
• Review cardiac function, rhythm, conduction, blood pressure and interacting medicines before prescribing.
• Use particular caution in hepatic impairment; renal impairment also warrants careful clinical monitoring.
• Intravenous use requires continuous ECG and blood-pressure observation.

Contraindications and cautions

• Cardiogenic shock, uncompensated heart failure or acute myocardial infarction complicated by bradycardia, marked hypotension or left ventricular failure.
• Second- or third-degree atrioventricular block, sinoatrial block or sick sinus syndrome without a functioning pacemaker.
• Atrial flutter or fibrillation with an accessory pathway such as Wolff–Parkinson–White syndrome.
• Concomitant ivabradine.
• Simultaneous intravenous beta-blocker therapy with intravenous verapamil.

Monitoring

• Blood pressure, pulse and symptoms of bradycardia, hypotension or heart failure.
• ECG where clinically relevant, including intravenous administration.
• Clinical response and adverse effects in hepatic or renal impairment.
• Bleeding when combined with direct oral anticoagulants.

Clinical pharmacology

Verapamil is a phenylalkylamine, non-dihydropyridine calcium antagonist with direct cardiac and peripheral vascular effects. It slows sinoatrial and atrioventricular nodal activity, reduces myocardial contractility and causes arterial and coronary vasodilation. It is also a CYP3A4 and P-glycoprotein inhibitor.

Formulation and product differences

• Modified-release tablets provide prolonged release and must not be chewed or crushed; follow product instructions concerning food and tablet splitting.
• The oral solution is an immediate-release option with additional product-specific contraindications and cautions.
• Injection is for slow intravenous hospital administration for specified supraventricular arrhythmias under continuous ECG and blood-pressure monitoring.
• Licensed indications are not interchangeable across formulations.

Oral solution

Route: Oral

Strengths: 40 mg/5 mL

Tablet

Route: Oral

Strengths: 120 mg, 240 mg

Injection

Route: Parenteral

Strengths: 2.5 mg/mL