Drug toxicity and hospitalization among lithium users.

Among a cohort of 921 outpatients less than 65 years of age at Group Health Cooperative of Puget Sound who took lithium during a 5-year period, lithium-associated toxicity leading to hospitalization was rare. In only one case (muscle fasciculation) was lithium directly implicated as the cause of hospital admission. In five cases described in detail (one case each of hyperparathyroidism, vasculitis, edema, brain stem infarction, and subarachnoid hemorrhage), an etiologic connection with lithium exposure was considered unlikely but could not be ruled out.