Effects of diuretics on renal excretory function.

From a clinicopharmacological standpoint, the urinary excretory potency of diuretics should be assessed comparatively, on the basis of placebo-controlled changes in 24 h natriuresis, following single oral doses administered to healthy adult subjects who are in steady-state habitual external sodium balance. The potency of 30 diuretic formulations has been evaluated. Two formulations of loop diuretics (muzolimine 20 mg and torasemide 2.5 mg) are non-diuretic. The majority of the other formulations of loop diuretics studied (e.g. furosemide 40 mg and torasemide 5 and 10 mg) are comparatively less potent than most of the common formulations of early distal tubular diuretics studied (e.g. hydrochlorothiazide 25 and 50 mg, xipamide 10, 20 and 40 mg). Hydrochlorothiazide 25 mg and furosemide 80 mg have similar potencies. The presence of a rebound in natriuresis between 6 and 24 h after administration of loop diuretics make the majority of the common formulations of these drugs less potent than most common formulations of thiazide-type diuretics.