Effect of age and route of administration on LD50 of lithium chloride in the rat.

Male inbred rats were used to determine the lethal dose of lithium chloride. The rats were 3 weeks, 6 weeks, 3 months and 6 months old, and lithium chloride was given intraperitoneally, subcutaneously and orally. In relation to age, LD50 was significantly higher in rats of 6 weeks after oral administration than LD50 in rats of 3 and 6 months. No differences were found following intraperitoneal and subcutaneous administration. In relation to route of administration, LD50 was significantly higher in rats of 3 and 6 weeks after oral administration than LD50 after intraperitoneal and subcutaneous administration. This difference was not found in rats of 3 and 6 months. It is concluded that age and route of administration are of significance for LD50 of lithium chloride in the rat.