Furosemide. A clinical evaluation of its diuretic action.

FUROSEMIDE (4 chloro-N[2-furyl methyl] -5-sulfamyl-anthranilic acid) (fig. 1) is a new and potent diuretic compound which is effective when given either orally or parenterally. Structurally it has in common with substituted thiazides a sulfamyl-benzene grouping. Animal studies have revealed it to be a most effective diuretic in both rats and dogs, resulting in maximum diuretic effects of up to two thirds of the glomerular filtration rate.1' 2 Clearance data,3 4 micropuncture studies,5 6 and stop-flow analyses7 indicate sites of action in both the proximal and distal tubules, including the ascending limb of the loop of Henle. Toxicological evaluation suggests an extremely wide margin of therapeutic safety.8'9 Clinical studies to date have indicated that it is extremely potent and well tolerated.10-14 The present study was undertaken to investigate the clinical effectiveness of furosemide in various edematous states and to elucidate further the characteristics of its diuretic action.