Long-term effects of indapamide: final results of a two-year Italian multicenter study in systemic hypertension.

To evaluate the antihypertensive efficacy and tolerability of a low-dose diuretic, indapamide, 2.5 mg once daily, was given to 248 patients with uncomplicated, mild to moderate hypertension for a period of 24 months. Blood pressure during sitting was 165 +/- 1/105 +/- 1 mmHg (mean +/- standard error of the mean) at the end of the placebo run-in period and 143 +/- 1/88 +/- 1 and 140 +/- 1/85 +/- 1 mmHg after 2 and 24 months, respectively; heart rate was clinically unmodified (from 77 +/- 1 to 75 +/- 1 beats/min). Total cholesterol, high-density cholesterol and serum triglycerides were unchanged, and uric acid increased significantly (from 292.0 +/- 6.5 to 377.7 +/- 56.5 mumols/liter). A mild reduction in serum potassium (-0.36 +/- 0.03 mmol/liter) was observed after 2 and 6 months of therapy; however, the degree of reduction appeared to be lower than that from reported studies with other thiazide diuretics. The incidence of hypokalemia (serum potassium less than 3.5 mmol/liter) was highest in northern Italy (17%), intermediate in the central region (14%) and lowest in southern Italy (2%), although the absolute reduction in serum potassium was similar in all the geographic areas. Blood glucose tolerance was unchanged despite the changes in serum potassium. The tolerability was good on the whole, with a tendency toward an improvement in the well-being of patients, most of whom were already asymptomatic before starting the study.