Spironolactone and hydrochlorothiazide in normal-renin and low-renin essential hypertension.

The relative blood pressure response and side effects of spironolactone (S), 400 mg/day, and hydrochlorothiazide (H), 100 mg/day, were evaluated in a double-masked crossed comparison. Subjects were 24 essential hypertensives, 13 normal and 11 with low renin activity. Upright renin levels were determined in the AM after 3 days of moderately low sodium diet (less than 100 mEq/day) and at the end of each drug treatment period. The values were not revealed to one investigator until completion of the study. After 4-week placebo control periods, either S or H was given in divided doses for 6 weeks. Blood pressure measurements and side effects were evaluated at biweekly intervals. The fall in blood pressure from control was the same for each drug and was independent of renin activity. Side effects occurred more often in patients treated with S, and H was judged superior by risk/benefit analysis. We conclude that S is no more beneficial than H in hypertensive patients with either low or normal renin activity but induces a higher incidence of adverse effects in the dose used in this study. We found no evidence for a greater effectiveness of S in low-renin essential hypertension.