Ethacrynic Acid: A Drug Which Abolishes the Concentrating Ability of the Kidney.

Studies to demonstrate the effect of ethacrynic acid on the urine concentrating ability of the kidney in maximally dehydrated humans and dogs have been described. Results indicate that the drug essentially abolishes TCH2O in association with a massive sodium diuresis. The most likely explanation of the effect on urine concentration is an inhibition of sodium transport in the ascending loop of Henle. Additional sodium blocking action at a site(s) other than the loop of Henle is postulated to account for the magnitude of the sodium diuresis.