Do all diuretics have equal hypotensive efficacy?

An open parallel study was carried out in general practice on 70 patients with uncomplicated mild to moderate hypertension to compare the hypotensive efficacy of hydrochlorothiazide/amiloride with that of cyclopenthiazide/potassium. After a 2-week baseline period on placebo, patients were allocated at random to receive treatment with one or other of the diuretics starting with 1 tablet per day and increasing up to a maximum of 4 tablets per day or until their supine diastolic blood pressure was 90 mmHg or less. They were then continued at their optimum dose for a further 4 weeks. Analysis of the results from 62 patients showed that the hydrochlorothiazide/amiloride preparation produced both a greater decrease and better control of blood pressure in a greater percentage of patients that did the comparison diuretic. In addition, the beneficial effects were attained with fewer tablets, of importance for patient compliance.