Double-blind comparison of triamterene plus hydrochlorothiazide and spironolactone plus hydrochlorothiazide in the treatment of hypertension.

The results from this double-blind, multi-investigator study showed that a combination of 50 mg triamterene plus 25 mg hydrochlorothiazide and a combination of 25 mg spironolactone plus 25 mg hydrochlorothiazide were equally efficacious in lowering blood pressure in hypertensive outpatients, and that they produced the same type and incidence of adverse effects. Likewise, the two drug combinations produced similar effects on blood chemistry and hematology. There were no significant differences between the two combination drugs in efficacy laboratory studies, or adverse effects.