Kidney function and response to lithium treatment.
1. Kidney function during long-term lithium treatment was studied in the representative sample of patients with recurrent affective disorders. Creatinine clearance, maximum urinary osmolality and 24-hour urine volume were determined. 2. Patients were divided according to their type of response to long-term lithium treatment, expressed by the effect on the frequency of recurrencies. Various indicators of kidney function were compared in excellent responders and in non-responders. 3. Long-term lithium treatment did not lead to any detectable changes of glomerular filtration in either group. 4. In comparison with responders, non-responders showed a significantly greater increase in 24-hour urine volume and a trend towards a greater reduction of maximum urinary osmolality, and thus a greater impairment of tubular function. 5. The findings stress the need for a careful selection of patients for long-term lithium stabilization.