Verapamil Dosing: BID vs Once Daily
For immediate-release verapamil, three times daily dosing (80-160 mg TID) is required, while sustained-release formulations can be dosed once daily up to 240 mg, but should be given twice daily when higher doses are needed for optimal 24-hour control. 1, 2
Immediate-Release Verapamil
- Immediate-release verapamil must be dosed three times daily (80-160 mg TID) due to its short half-life and brief duration of action 1
- This formulation is not suitable for once or twice daily dosing given its pharmacokinetic profile 3
Sustained-Release Verapamil Formulations
Once Daily Dosing
- Sustained-release verapamil can be administered once daily for doses up to 240 mg 2, 3
- The FDA-approved dosing for hypertension starts at 180 mg once daily in the morning, with lower initial doses of 120 mg warranted in elderly or small patients 2
- Once-daily dosing provides adequate 24-hour blood pressure control at these lower doses 3, 4
Twice Daily Dosing (BID) - Superior for Higher Doses
- When doses exceed 240 mg daily are required, BID dosing is superior and should be used 2, 3, 5
- For hypertension not controlled with 180 mg once daily, titration options include: 240 mg each morning plus 120 mg each evening, or 240 mg every 12 hours 2
- For angina, verapamil-SR 240 mg BID is superior to once-daily regimens for 24-hour prophylaxis, demonstrating significantly longer exercise duration (704 vs 648 seconds, p=0.03) and greater time to 1 mV ST depression (+11%, p=0.04) compared to placebo 5
- BID dosing of 240 mg provides more consistent peak-to-trough plasma levels and better symptom control throughout the 24-hour period 4, 5
Clinical Considerations by Indication
Hypertension
- Initial therapy: 180 mg once daily with food 2
- If inadequate response: titrate to 240 mg once daily, then consider split dosing (180 mg AM + 180 mg PM, or 240 mg AM + 120 mg PM) 2
Angina Pectoris
- 240 mg BID emerges as the optimal regimen for chronic stable angina, reducing weekly anginal episodes from 6.4 to 2.8 (p=0.06) 5, 6
- This BID regimen is as effective as immediate-release verapamil 120 mg four times daily but with improved compliance 6
Arrhythmias (Acute Management)
- For acute supraventricular tachycardia: IV verapamil 2.5-5 mg over 2 minutes (over 3 minutes in elderly), may repeat 5-10 mg every 15-30 minutes to total 20 mg 1
- Oral maintenance dosing would follow sustained-release guidelines above
Important Caveats
- Avoid verapamil in patients with severe LV dysfunction, heart failure, pulmonary edema, PR interval >0.24 seconds, or second/third-degree AV block without pacemaker 1
- Sustained-release formulations should be taken with food to avoid high peak blood levels, though newer pellet-filled capsule formulations (Verelan) can be taken without food 3
- When switching from immediate-release to sustained-release, the total daily dose in milligrams may remain the same 2
- Edema is a common dose-dependent side effect, particularly affecting lower extremities 1, 7