Studies on the saluretic and antihypertensive action of indapamide

Summary results of maximal water diuresis and osmolar clearance studies in 6 volunteer patients with essential hypertension it was concluded that indapamide had a mild saluretic effect and acted in man by selectively blocking salt reabsorption in the cortical diluting zone of the ascending branch of Henle's loop. A double-blind placebo-controlled study was carried out in 47 hypertensive patients to assess the effectiveness of indapamide (2.5 mg/day) as a hypotensive agent. After a 2-week period on placebo, patients received indapamide for 8 weeks and were finally returned to placebo treatment for a further 2 weeks. Systolic and diastolic blood pressures, measured in both recumbent and standing positions, showed a significant reduction from placebo levels. The major reduction occurred during the first 4 weeks of treatment, the levels being maintained whilst on indapamide but increasing significantly again when the active drug was replaced by placebo. Little change in heart rate was recorded, no side-effects were reported, and there were no significant changes from normal limits in the biochemical parameters investigated.