Hypotensive effects of xipamide in essential hypertension. Crossover comparison with hydrochlorothiazide

Twenty-nine patients with mild to severe essential hypertension were treated with titrated doses of xipamide, before or after treatment with 50 and , if necessary, 100 mg hydrochlorothiazide in a 13- to 25-week open crossover study. Based on supine diastolic pressure readings taken at weekly intervals, xipamide controlled hypertension in all subjects: 17 achieved control with a daily dose of 5 mg; seven, with 10 mg; and five, with 20 mg. In contrast, eight of the 29 patients could not be controlled with 100 mg/day hydrochlorothiazide. The only significant biochemical change observed was an increase in serum uric acid in 12 patients after hydrochlorothiazide but in only six patients after xipamide. Natriuresis was comparable after both drugs; 5 and 10 mg xipamide were as effective as 50 and 100 mg hydrochlorothiazide. The only side effect noted, cramping due to hypokalemia, occurred during treatment with hydrochlorothiazide, but not xipamide, and was reversed by potassium supplements.