From the Guidelines
Verapamil SR is approved for both once-daily and twice-daily dosing, depending on the specific formulation and patient needs, as indicated by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. The once-daily formulation (typically Verapamil SR 240 mg) is designed to maintain therapeutic blood levels over 24 hours, while some patients may require twice-daily dosing (often 120-180 mg twice daily) for optimal blood pressure control or management of angina. Some key points to consider when prescribing Verapamil SR include:
- The specific dosing schedule depends on the particular branded or generic formulation being used, as different manufacturers produce versions with varying release characteristics.
- When initiating therapy, clinicians often start with lower doses and titrate based on patient response and tolerability, monitoring for side effects such as constipation, headache, or hypotension.
- The extended-release technology in verapamil SR formulations allows for more consistent calcium channel blockade throughout the dosing interval compared to immediate-release versions, resulting in smoother blood pressure control and reduced fluctuations in drug levels that might otherwise lead to adverse effects. According to the 2015 ACC/AHA/HRS guideline, Verapamil can be administered in a daily dose of 120 mg, which can be given in divided or single dose with long-acting formulations, with a maximum daily dose of 480 mg 1. It's also important to note that Verapamil is a moderate CYP3A4 inhibitor and also inhibits P-glycoprotein, and it has several potential interactions with other medications, including itraconazole, bosutinib, ceritinib, cilostazol, colchicine, cyclosporine, everolimus, dabigatran, edoxaban, flecainide, ibrutinib, ivabradine, olaparib, ranolazine, rivaroxaban, rifampin, silodosin, simeprevir, simvastatin, topotecan, trabectedin, vincristine, and grapefruit juice 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Essential hypertension: ... Initiate therapy with 180 mg of sustained-release verapamil HCl, verapamil hydrochloride extended-release tablets, given in the morning ... 180 mg each morning plus 180 mg each evening; or 240 mg each morning plus 120 mg each evening, 240 mg every 12 hours
- The dosing frequency of verapamil SR is not limited to only once daily, as it can be given in divided doses, such as 180 mg each morning plus 180 mg each evening, or 240 mg every 12 hours.
- Approved dosing includes options for both once daily and divided doses, depending on the patient's response and therapeutic needs 2.
From the Research
Verapamil SR Dosing
- Verapamil SR dosing is not limited to only once daily, as it can be administered twice daily when higher doses are needed 3.
- A sustained-release formulation of verapamil allows for once-daily dosing up to 240 mg/d, but higher doses require twice-daily administration 3.
- A new pellet-filled capsule formulation of verapamil (Verelan) provides controlled absorption, 24-hour blood pressure control, and once-daily dosing regardless of dosage size 3.
- Other studies also support the use of sustained-release verapamil formulations for once-daily dosing, with equivalent efficacy to conventional verapamil formulations given 3 times daily 4.
- However, some studies suggest that sustained-release verapamil can be given twice a day, especially in patients with angina pectoris or hypertension 5.