Addition of chlorthalidone to slow-release nifedipine in the treatment of arterial hypertension: A controlled study versus placebo

Summary The use of calcium antagonists and diuretics in combination for treatment of hypertension is controversial.In a single-blind study 16 patients (8 men, 8 women, age range 39 to 62 years) with primary hypertension of mild to moderate degree were given slow-release nifedipine 20 mg twice daily for 6 weeks, thereafter either chlorthalidone 25 mg (Group A) or placebo (group B) daily was randomly added for a further 6-week period.Blood pressure (BP), heart rate, plasma renin activity (PRA), aldosterone, and 24 hour urinary electrolytes were evaluated.Nifedipine decreased supine BP from 159/92±16/8 to 151/89±10/6 mmHg in group A and from 162/94±20/12 to 145/85±14/6 mmHg in group B. A further fall to 139/84±7/6 mmHg (p<.05) was observed after addition of chlorthalidone.PRA significantly increased with combined treatment compared to baseline (3.3±0.8 to 9.9±3.3 ng/ml/hr;p<0.05). A slight reduction of 24-hour urinary calcium was observed after the addition of chlorthalidone.These data indicate that the combination of nifedipine and chlorthalidone might be beneficial in the treatment of arterial hypertension.