Site of action of diuretic drugs

Abstract

The availability of many different diuretic drugs that can selectively inhibit one or more of a variety of transport processes within the nephron provides a wide range of options that can be rationally used in the treatment of edema states and nonedematous disorders. Caution must be exercised before the results at a segmental level of the nephron can be extrapolated to whole kidney in vivo performance. For instance, hemodynamic effects, changes in ECF volume, intratubular pressure, tubular fluid flow rate, or electrolyte composition, etc., may all exert effects on solute transport independently of any direct effect of the drug in a particular nephron segment. Many questions remain unanswered. The effects of certain diuretics upon proximal tubular transport are still unsettled and the results of in vivo experiments have not been reconciled with in vitro studies in the isolated perfused tubule. The mechanism whereby carbonic anhydrase inhibitors affect sodium and chloride transport is still unclear as is the extent to which such effects can account for the proximal action of thiazide diuretics. The answers to these and many other issues that have been raised by such studies require much further work and will undoubtedly contribute to a better understanding of the physiology of the kidney.