Long-Acting and Short-Acting Diuretics in Mild Essential Hypertension

Publisher Website
Google Scholar
Abstract
A randomized, placebo-controlled, double-blind crossover study was conducted in 14 patients with mild essential hypertension, comparing different regimens of administration of the short-acting diuretic chlorothiazide and the long-acting diuretic chlorthalidone. There were 6 randomized treatment phases, each of 5 wk duration. For blood pressure recorded both at the clinic and at home, the most prominent effects were seen with standing blood pressure, for which significant reductions of mean blood pressure compared to the placebo phase were observed with chlorthalidone 25 mg once daily (-5 .+-. 1 (SE) mm Hg, P < 0.05), chlorthalidone 50 mg once daily (-7 .+-. 1 mm Hg, P < 0.01) and chlorothiazide 500 mg twice daily (-4 .+-. 1 mm Hg, P < 0.05). Blood pressure reductions with chlorothiazide 500 mg once daily and 1000 mg once daily were not significant. About 1/2 of the patients completing the trial could be described as nonresponders. The observed biochemical changes (reduced plasma K and Cl concentrations and increased plasma bicarbonate and urate concentrations) were most marked in the phases with the most prominent blood pressure effects. Apparently, a sustained diuretic effect is desirable when diuretics are used in the treatment of hypertension. This can be obtained by selection of the appropriate dosage regimen for a particular diuretic, such as once daily administration for long-acting and twice daily for short-acting thiazide-type diuretics.