Diuretic profile of a novel loop diuretic torasemide in rats and dogs

In the present study, the authors have examined the diuretic action of a novel loop diuretic torasemide and compared it to those of other diuretics, employing normal rats and dogs. Oral administration of torasemide elicited a dose-dependent increase in urine volume and electrolyte excretion, and elevated the urinary Na/K ratio in rats. These effects were more potent than those of the other diuretics furosemide, trichlormethiazide, indapamide and spironolactone. Moreover, torasemide exhibited a similar or higher urinary Na/K ratio than the combination of these diuretics and spironolactone. In a study employing anaesthetized dogs, i.v. injection of torasemide resulted in a higher urinary Na/K ratio in comparison to furosemide, in addition to potent and long-lasting diuretic activity.