Effectiveness of once-daily monotherapy with a new nifedipine sustained release calcium antagonist

Abstract

Data from 2 separate multicenter, double-blind clinical studies following the same protocol, except for the selection of doses, were pooled to evaluate the efficacy and tolerability of fixed doses of a new sustained-release (SR) formulation of nifedipine compared with placebo in 388 patients wtth mild to moderate uncomplicated essential hypertension. After a 3–6 week placebo washout period, the patients were randomized to receive either placebo or nifedipine SR-20 mg (study I only), 50 mg, 100 mg, or 150 mg (study II only). Among the 278 patients who completed 6 weeks of active therapy, mean supine diastolic blood pressure reductions from pretreatment baseline were 5.9,9.3,9.2,111, and 13.2 mm Hg hi the placebo, 20-, 50-, 100-, and 150-mg groups, respectively. The reductions achieved in each of the nifedipine SR groups were statistically significant versus baseline values (p <0.001). All nifedipine-SR doses reduced supine systolic blood pressure significantly more than placebo (p <0.001). In addition, there was a significant linear relationship between the log of the dose and the blood pressure reduction (p <0.05). Automated ambulatory blood pressure recordings performed in 221 of the patients showed that the blood pressure was lowered evenly through the entire 24-hour dosing period. The doses that were effective and associated with the fewest adverse reactions were 20 mg and 50 mg once daily.