A preventive effect of potassium against fatal lithium intoxication in rats.

The effect of potassium against lithium intoxication was studied in two groups of rats given food containing 100 mmol of sodium and 100 or 1,100 mmol of potassiam/kg dry weight. After 1 week 80 mmol of lithium chloride/kg dry weight was added to both diets. Four days later the body weight, serum lithium concentration, and urinary lithium clearance were all significantly higher in the high potassium group than in the other group. After 15 days the lithium clearance had fallen to one fifth in the lowest potassium group but was unaltered in the high potassium group. All rats in the low potassium group continued to lose weight and died of lithium intoxication within 20 days, while the rats given high potassium survived and gained weight. A high potassium content of the food was able to prevent a fatal lithium-induced loss of sodium and to maintain a normal lithium clearance. It is suggested that also a lithium-induced loss of potassium was counteracted.