Renal Function of Patients in Long-term Treatment With Lithium Citrate Alone or in Combination With Neuroleptics and Antidepressant Drugs

• Renal function was studied in patients given lithium citrate alone or in combination with neuroleptics or tricyclic antidepressants or both. No other drugs were given. None of the groups given lithium citrate with other drugs had lithium ion clearances that differed significantly from the groups given lithium citrate alone, nor was there any difference in the clearances of sodium, potassium, or creatinine between these groups. The 24-hour urine volume of patients receiving antidepressant drugs was similar to that of the patients receiving lithium citrate monotherapy but was significantly higher in patients given neuroleptics. The increase in urine volume could not be ascribed to alterations in glomerular filtration rate or proximal tubular resorption but could be accounted for entirely by lowered resorption of water in the distal tubules. We concluded that no change of lithium citrate dose is required when patients so treated are given additional neuroleptic or tricyclic antidepressant drugs.