Late side effects of lithium treatment.

Many patients have now been given lithium for 10-15 years, and the overall picture as regards late side effects is not alarming. Changes of renal morphology and function currently attract interest. Histologically demonstrate interstitial nephropathy may be observed in 10-15% of patients, but glomerular filtration rate is little affected or unaffected, and the risk of progressive renal failure with terminal azotemia is remote even in patients given lithium for many years. Renal water reabsorption is often impaired, and the patients may develop polyuria or lowered concentrating ability. These changes are not in themselves dangerous, but since dehydration may lead to lithium poisoning, the patients should drink extra water during situations with risk of a negative water balance.