Demeclocycline in the prophylaxis of self-induced water intoxication.

Demeclocycline, a competitive inhibitor of antidiuretic hormone at renal tubules, was studied in a patient with the syndrome of psychosis, psychogenic polydipsia, and episodic water intoxication. Under double-blind, placebo-controlled conditions, demeclocycline substantially reduced the severity and frequency of hyponatremic episodes.