Treatment of the syndrome of inappropriate secretion of antidiuretic hormone with lithium carbonate.

Lithium, an established inhibitor of antidiuretic hormone action, was used (as the carbonate salt) to treat a patient with the syndrome of inappropriate secreation of antidiuretic hormone. The patient was studied by balance technics, and after a stablized hyponatremic state developed, 0.9 g of lithium carbonate was administered daily. A prompt water diuresis ensued, with correctionof hyponatremia in two days. Discontinuation of the drug resulted in a gradual return of the hyponatremic state. No change in urinary cyclic AMP occurred during the period of lithium effect. Lithium carbonate may be an effective treatment for both the acute and the chronic forms of the syndrome.