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

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 with 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, 11.1, and 13.2 mm Hg in 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 less than 0.001). All nifedipine-SR doses reduced supine systolic blood pressure significantly more than placebo (p less than 0.001). In addition, there was a significant linear relationship between the log of the dose and the blood pressure reduction (p less than 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.