Furosemide compared with hydrochlorothiazide. Long-term treatment of hypertension.

In a double-blind crossover study, the effectiveness of furosemide, 40 mg twice daily, was compared with hydrochlorothiazide, 50 mg twice daily, in hypertensive patients. Both hydrochlorothiazide and furosemide significantly reduced blood pressure (BP) during three months of therapy. However, the fall in BP was consistently greater with hydrochlorothiazide than with furosemide, although the difference was significant only with respect to systolic BP. The somewhat greater antihypertensive effectiveness of hydrochlorothiazide may be related to its longer action permitting a more continuous diuretic effect and, hence, maintenance of reduced extracellular fluid volume throughout the 24-hour period.