Treatment of benign essential hypertension: comparison of furosemide and hydrochlorothiazide.

Furosemide (Impugan) 12.5, 25 or 40 mg twice daily, has been compared as an antihypertensive with hydrochlorothiazide 12.5 mg twice daily and a placebo. A double blind, cross-over design was used with a run-in period of 4 weeks, preceding five 4-week periods of treatment with these compounds alone. There were 34 patients in the trial, 17 men and 17 women. Paired comparison showed that furosemide 25 or 40 mg twice daily and hydrochlorothiazide 12.5 mg twice daily had a similar hypotensive effect, irrespective of the initial blood pressure. Furosemide 40 mg twice daily and hydrochlorothiazide 12.5 mg twice daily caused a slight fall of blood pressure as compared with placebo (0.10 greater than p greater than 0.05, p less than 0.05). There was a distinct correlation between blood pressure and age. Serum K+ fell significantly during treatment, particularly with hydrochlorothiazide 12.5 mg twice daily, as well as with furosemide 25 or 40 mg twice daily. As compared with placebo, urinary output increased significantly after furosemide 12.5, 25 or 40 mg twice daily, but it rose only to a non-significant extent after hydrochlorothiazide. The fall of blood pressure and decrease in serum K+ were linearly related. There were only a few, mild side effects which did not necessitate discontinuation of the trial.