Torasemide, a new potent diuretic. Double-blind comparison with furosemide

The pharmacodynamic effects of torasemide, a new potent loop diuretic, were compared with those of furosemide in a double blind controlled study in 18 hypertensive patients with oedema of various origins. Given orally for 5 days, torasemide was clinically very effective and well tolerated. On a weight basis, the diuretic, natriuretic and chloruretic effects of torasemide were about 8-times greater than those of furosemide. However, the kaliuretic effect of torasemide was only 3-times greater than that of furosemide, suggesting that torasemide is more potassium sparing than furosemide. Torasemide displayed a rapid onset of action, similar to that of furosemide but had a longer diuretic effect without any rebound phenomenon. Torasemide and furosemide did not effect creatinine clearance or uric acid excretion. Both furosemide and torasemide lowered systolic blood pressure but the effect of torasemide was more marked than that of furosemide. In this group of aged and hypertensive patients with oedema, the pharmacokinetics of torasemide was comparable to that reported in young healthy volunteers, and were similar on the first and fifth days of treatment. The long duration of action and the potassium sparing effect of torasemide compared to furosemide are promising features of this new loop diuretic in the treatment of oedema and hypertension.