Severe sodium depletion syndrome during lithium carbonate therapy

Lithium carbonate, useful in the treatment of manic-depressive disorders, can produce nephrogenic diabetes insipidus. The drug, therefore, has been used to facilitate renal waster excretion when severe hyponatremia occurs in the syndrome of inappropriate antidiuretic hormone secretion. Symptomatic dilutional hyponatremia developed in a patient with pulmonary carcinoma whom we treated. Lithium carbonate was administered and renal sodium wasting, hypovolemia, and hypotension occurred. Hyperkalemia was also observed, and since adrenal steroid levels were not decreased, impairment of distal tubular function was suggested. Lithium carbonate blocks antidiuretic hormone effect by decreasing collecting duct cyclic adenosine monophosphate generation. These observations suggest that more generalized inhibitory effects on renal tubular function may also result from its use. An alternative drug, demeclocycline, may be preferable.