The Relationship of Dose to the Antihypertensive Response of Verapamil‐Sustained Release in Patients with Mild to Moderate Essential Hypertension

Publisher Website
Google Scholar
Abstract
The dose‐response relationship of verapamil‐SR was studied in 221 hypertensive patients. This double‐blind, parallel‐group, placebo‐controlled study compared placebo to 60 mg, 120 mg, 240 mg and 480 mg doily of verapamil‐SR. After 6 weeks of therapy, peak diastolic blood pressure was similar in the placebo group and the verapamil‐SR 60 mg group, 93.0 and 92.0 mmHg, respectively. The 120 mg, 240 mg and 480 mg verapamil‐SR groups produced significantly lower diastolic blood pressure, 89.8, 85.3 and 83.7 mmHg (P < 0.01), respectively. At trough, placebo and verapamil‐SR 60 mg groups and 120 mg groups had diastolic blood pressures of 96.6, 97.0 and 97.1 mmHg, respectively. Diastolic blood pressure with the 240 mg dose (92.4 mmHg) was significantly lower than with the 120 mg dose (P < 0.01). The 480 mg dose resulted in a diastolic blood pressure of 88.6 mmHg, which was significantly lower than the 240 mg dose (P < 0.01). The responder rate with 240 mg at peak was 82%. The trough to peak ratio was 0.58. Plasma concentrations were highly correlated with dose (r > 0.8; P < 0.01); but not with diastolic blood pressure (r > 0.4; P < 0.01). Headache and constipation, although not significantly different from placebo, were the most commonly reported adverse reactions in the verapamil‐SR groups, 6.3% (placebo—6.7%) and 5.1% (placebo—4.4%), respectively. Graded doses of verapamil‐SR produced a dose‐response curve in hypertensive patients with a greater than 80% responder rate at the 240 mg dose. Therefore, 240 mg of verapamil‐SR is effective monotherapy in the majority of patients.