Acute antihypertensive, diuretic and metabolic effects of etozolin and chlorthalidone

Etozolin, a new diuretic agent, has shown a dose-dependent diuretic and saluretic effect in both experimental and clinical studies. Etoxolin, when compared to furosemide or thiazides, exerts a similar effect on urinary excretion of water and Na+, but induces a lower urinary K+ and Cl- excretion and a smaller activation of the renin-angiotensin-aldosterone system. Furthermore, the E series of the prostaglandin system seems to play a role in the mechanism of action of the drug. Seven uncomplicated hypertensive patients were included in this double blind, placebo controlled study, according to a latin square design. Each patient received three single oral doses of etozolin (200 mg, 400 mg, 600 mg), of chlorthalidone (25 mg, 50 mg, 75 mg) and one dose of placebo. Etozolin and chlorthalidone caused a similar, dose-dependent antihypertensive and diuretic effect. However, several haemodynamic and metabolic differences were observed between the two drugs. Etozolin, unlike chlorthalidone, caused no increase of heart rate, no decrease of serum K+ levels and a marked rise plasma PGE2. Moreover, etozolin caused a significantly smaller decrease of serum Na levels compared to chlorthalidone, and a significantly lower increase of supine and standing PRA, of plasma aldosterone and of the urinary excretion of Na and K. These results confirm that the acute antihypertensive and diuretic activity of etozolin occur with little involvement of the RAA system and with a significant but still unclear activation of the prostaglandin system.