Long-Term Effects of Furosemide and Hydrochlorothiazide in Patients With Essential Hypertension

Abstract

In a double-blind study the long-term effects of diuretics in uncompli cated mild and moderate essential hypertension were investigated. A total of 52 outpatients completed 24 months of treatment with either furose mide at a dose of 40 mg twice daily (26 patients) or hydrochlorothiazide at a dose of 50 mg twice daily (26 patients). Throughout the 2 years of the study, both furosemide and hydro chlorothiazide significantly lowered the mean supine blood pressure from baseline levels. The fall was less with furosemide than with hydrochloro thiazide, although the difference between the two drugs reached statistical significance at only three of the eight time points. Serum electrolytes were used as major indicators of safety. The cumulative incidence of hypokalemia of 8% for the furosemide group compared to that of 62% for the hydrochlorothiazide group. Although diuretics, alone or combined with other blood pressure-lower ing drugs, have been used for many years to treat essential hypertension, information on their continued efficacy and safety is scarce. Short-term trials had shown that furosemide (Lasix(®)) resembled the thiazides in its antihypertensive properties,1-3 despite its different mode of action on the kidney. A cooperative study in hypertensive patients was therefore under taken at three clinical centers to investigate the long-term effects of furose mide on blood pressure and on serum electrolytes, and to compare them with those of hydrochlorothiazide.