Furosemide and hydrochlorothiazide were compared for treatment of black patients with mild to moderate hypertension in a randomized, open-label, crossover study design. Hydrochlorothiazide produced a significantly greater fall in mean arterial (24.7 vs 16.0 mm Hg, P <.01) and diastolic (17.3 vs 10.1 mm Hg, P <.01) blood pressure (BP) in 16 patients. Addition of methyldopa in nine patients produced a significantly greater fall in mean arterial (38.8 vs 31.9 mm Hg, P <.05) and diastolic (28.9 vs 23.4 mm Hg, P <.05) BP with hydrochlorothiazide vs furosemide. Renin status was categorized before and after treatment. Patients with low and normal renin activity were equally responsive to both diuretics. Hydrochlorothiazide caused a greater reduction in plasma potassium (0.26 mEq/L). Serum parathyroid hormone was not chronically elevated with furosemide. In this study, hydrochlorothiazide was more effective than furosemide for treatment of mild to moderate hypertension in black patients; renin classification did not predict diuretic responsiveness.
(Arch Intern Med 139:1015-1021, 1979)