Prospective studies on a lithium cohort. 2. Renal function. Water and electrolyte metabolism.

A cohort of manic-depressive patients given prophylactic lithium treatment were examined before treatment started and at intervals during treatment for up to 7 years. The mean lithium dosage was 23.2 mmol/d and the mean serum lithium concentration 0.68 mmol/l. The treatment did not affect glomerulus function. Urine volume rose by 10-20% and renal concentrating ability fell by 7-10% during the treatment. These changes were markedly smaller than those found in patients treated previously with higher lithium doses and serum lithium concentrations. High urine volumes and low renal concentrating abilities were not more frequent during than before lithium treatment. Complaints of increased thirst, frequent urination, and nycturia were presented more often during than before lithium treatment. Serum concentrations, urinary excretions and renal clearances of sodium and potassium were not altered by the treatment.