Clinical efficacy and safety of indapamide in essential hypertension.

Indapamide, a new methylindoline diuretic that appears to act on the distal renal tubules, is also reported to reduce vascular smooth muscle vasopressor reactivity and possibly to have a calcium-antagonist effect. Since 1973, sixteen studies by a number of European investigators who treated 301 patients with indapamide have revealed satisfactory control in 53% of patients with mild hypertension (standing diastolic pressures less than 90 mm Hg) and in 43% of patients with moderate hypertension when the drug was used without other agents. Multiple American clinical trials of indapamide in hypertension have been conducted, including double-blind, placebo-controlled protocols and trials comparing indapamide with traditional diuretic agents. A cooperative, double-blind, 40-week study compared antihypertensive response to indapamide, 2.5 mg and 5 mg daily, with response to hydrochlorothiazide, 50 mg daily, in the treatment of mild to moderate hypertension. Pretreatment diastolic blood pressures averaged 101 mm Hg. At 40 weeks of treatment, indapamide, 2.5 mg daily, had produced a fall in diastolic pressure of 15 mm Hg; indapamide, 5 mg daily, a reduction of 16 mm Hg; and hydrochlorothiazide, 50 mg daily, a fall of 15 mm Hg. Seventy-five percent of patients taking 2.5 mg of indapamide daily and 88% of those taking 5 mg achieved satisfactory blood pressure reduction. Hypokalemia may occur with indapamide but is a minor problem and seldom necessitates potassium supplementation. Serum uric acid increases were observed in only a few subjects, and clinical side effects are infrequent and mild. Indapamide is a useful antihypertensive agent with good patient tolerance in mild or moderate hypertension and may offer advantages over traditional diuretics in view of its possible vasodilator and calcium-antagonist properties, once-a-day dosage, and good therapeutic effect with prolonged usage.