Plasma demeclocycline levels and nephrotoxicity. Correlation in hyponatremic cirrhotic patients.

In five hyponatremic, cirrhotic patients, demeclocycline hydrochloride was used to inhibit the hydroosmotic effect of vasopressin. In four, renal impairment developed during the 7 to 20 days of demeclocycline hydrochloride (900 to 1,200 mg/day) administration. In these four patients, creatinine clearance fell (72 to 20 mL/min, P less than .01) as BUN (12 to 47 mg/dl, P less than .02) and serum creatinine (0.9 to 4.2 mg/dl, P less than .01) levels rose. The azotemic effect of the drug could not be accounted for consistently by volume depletion secondary to its natriuretic effect. However, a close correlation between plasma demeclocycline levels and its azotemic effect was observed. We conclude that a nephrotoxic effect of demeclocycline severly limits its usefulness in treating hyponatremia in the cirrhotic patient.