Antihypertensive and biochemical dose-response study of tripamide.

Tripamide is an experimental sulfonamide-derived diuretic antihypertensive agent. Twenty-four hospitalized patients with essential hypertension received placebo followed by 10, 25, 50, or 100 mg of tripamide daily in a randomized, double-blind design. All doses of tripamide significantly lowered standing arterial pressure. Changes in blood pressure, heart rate, and weight were not dose related, but the decrease in mean arterial pressure was significantly related to both age (P less than 0.02) and pretreatment blood pressure (P less than 0.05). Serum potassium levels were lowered significantly by the 25 and 100 mg daily doses of tripamide, whereas all doses of tripamide significantly reduced serum chloride levels and produced an increase in serum uric acid levels. Disparate time courses of antihypertensive and diuretic effects and the lack of a relationship between the increase in urine volume and the change in blood pressure suggest an additional antihypertensive action of tripamide or a delayed physiologic adaptation to volume depletion. Equal antihypertensive effects over the range of 10 to 100 mg/day, but greater hypokalemia at higher doses, suggest that future studies should employ the lower doses of tripamide.