Renal function after long term treatment with lithium.

Renal functions of 30 patients of manic depressive psychosis on long term lithium prophylaxis have been studied and compared with 15 age and sex matched patients receiving psychotropic drugs other than lithium. The urine output more than 2.5 L/day was seen in 12 patients (4(1% ) while impaired capacity to show urinary osmolality more than 500 m Osm/L after overnight fluid deprivation was seen in 6 patients. Creatinine clearance ranged between 70-106 ml/min (mean 89 ml/mt). Creatinine clearance less than 70 ml/nun was seen in 3 patients. The ratio of urinary and serum creatinine showed statistically significant (p< .001) low value in lithium treated group. There was also significant increase in mean uric acid excretion in patients on lithium therapy. It is recommended that inspite of serum lithium levels being in normal range, renal functions should be assessed regularly in order to avoid progressive impairment of renal functions.