From the Guidelines
Verapamil for atrial fibrillation is typically started at 5-10 mg intravenously over 2-3 minutes, with a possible repeat dose of 10 mg after 30 minutes if needed, as recommended by the most recent guidelines 1. When using verapamil for afib, heart rate and blood pressure should be monitored regularly as the medication can cause hypotension and bradycardia.
- Key considerations for verapamil use in afib include:
- Avoiding use in patients with heart failure, hypotension, sick sinus syndrome, or those taking beta-blockers due to risk of severe bradycardia or heart block 1
- Monitoring for common side effects such as constipation, headache, and dizziness 1
- Being aware of the potential for drug interactions, particularly with digoxin 1 Verapamil works by blocking calcium channels in the heart, which slows conduction through the AV node, thereby controlling ventricular rate in atrial fibrillation. The recommended dosing regimen is based on the most recent and highest quality study available, which prioritizes patient safety and efficacy in managing atrial fibrillation 1. It is essential to follow the guidelines and recommendations for verapamil use in afib to minimize risks and optimize patient outcomes. In terms of oral dosing, verapamil can be started at 120-360 mg daily in divided doses, with slow release available, as outlined in the guidelines 1. However, the initial intravenous dose is crucial for immediate rate control in acute atrial fibrillation, and the recommended dose of 5-10 mg intravenously over 2-3 minutes should be followed 1.
From the Research
Verapamil Dose for Atrial Fibrillation
- The mean administered dose of verapamil for controlling heart rate in patients with atrial fibrillation was 5.4±1.6 mg, as reported in a study published in 2025 2.
- In another study from 1983, oral verapamil therapy of 240 mg was found to be superior to digoxin in treating chronic atrial fibrillation 3.
- A 1985 study compared the effects of diltiazem and verapamil in patients with chronic atrial fibrillation, with verapamil doses ranging from 240 mg/d to 480 mg/d 4.
- A study from 1992 examined the efficacy and safety of quinidine and verapamil (240 mg/day) in patients with atrial fibrillation, with results showing a "rate-smoothing" effect on atrioventricular conduction 5.
- Another study from 1994 reported similar findings, with quinidine and verapamil (240 mg/day) increasing mean cycle length by 57 ms (8%) during atrial fibrillation 6.
Adverse Events and Safety
- A 2025 study found that 28 patients (12.6%) suffered from hypotension, and two patients had bradyarrhythmias after intravenous verapamil administration 2.
- The same study reported that within 7 days, cardiovascular death occurred in three patients (1.3%) 2.
- A 1985 study reported adverse reactions to verapamil, including dyspnea, pulmonary congestion, skin rash, and hepatotoxicity, leading to the withdrawal of three patients 4.