The impact of long-term lithium treatment on renal function and structure.

The effects of long-term lithium treatment on kidney function have been intensively studied. Both retrospective and prospective functional studies have shown that prolonged lithium treatment has a profound influence on renal tubular function, and may result in reduced renal concentrating capacity and increased urine volumes. More important, long-term lithium administration at non-toxic serum levels has little demonstrable or no effect at all on glomerular function. Prospective studies found no evidence of a progressive impairment of renal clearance. Renal biopsy studies have shown significant histopathological changes in patients with acute lithium intoxication, but only a slight degree of morphological injury in patients with no episodes of lithium poisoning. Other factors than lithium may contribute (e.g. analgesic abuse) or predispose (e.g. pyelonephritis) to similar changes. The lithium dosage schedule may represent an important factor.