EFFICACY OF A LOW-DOSE NIFEDIPINE GITS (20 MG) IN PATIENTS WITH MILD-TO-MODERATE HYPERTENSION

Nifedipine gastrointestinal therapeutic system (GITS) is a once-a-day formulation of nifedipine providing stable plasma concentrations over the entire 24 h dosing interval. The antihypertensive efficacy of a ne w 20 mg formulation was evaluated in 187 patients in 15 centres across the country. After a two-week placebo washout, mild to moderate hyper tensive patients were randomized in a double-blind, parallel design to four weeks of placebo or nifedipine GITS 20 mg once daily treatment. Changes in office blood pressure (BP) were noted for each group. Ambul atory BP was also monitored at baseline and after four weeks of placeb o/nifedipine therapy in a subgroup of 66 patients at five centres. Aft er four weeks of treatment, office BP in the placebo group decreased b y 5.0+/-11.9/5.4+/-7.9 mmHg compared with 9.3+/-11.2/8.6+/-7.4 mmHg in the nifedipine GITS group. Both systolic and diastolic BP were signif icantly decreased (P=0.006 and P=0.001 for systolic and diastolic, res pectively) more with nifedipine GITS. Heart rate did not significantly differ between the groups at baseline nor after four weeks of treatme nt. The percentage of responders - defined as having a sitting diastol ic BP less than 90 mmHg or a decrease from baseline of 10 mmHg - was 5 7% for nifedipine GITS versus 32% for placebo (P<0.05). Daytime averag e diastolic blood pressure was 86.4+/-6.4 mmHg in the nifedipine GITS 20 mg group compared with 93.7+/-8.9 mmHg in the placebo group (P<0.02 ). The maximum antihypertensive effect of nifedipine during ambulatory monitoring was similar to the reduction in BP observed in the office at the end of the dosing interval. The frequency of spontaneously repo rted adverse events was similar for nifedipine GITS (32.3%) and placeb o (37.2%). These results indicate that 20 mg of nifedipine GITS is eff icacious in decreasing BP, with good 24 h control and an incidence of adverse events similar to that of placebo-treated patients.