The effect of fasting on oral acute toxicity of drugs in rats and mice

Abstract

The oral acute toxicity of 3 β-adrenoceptor stimulants, 2 β-adrenoceptor blockers, and 2 anti-gastric ulcer drugs was studied in 8-week old, SD-JCL rats and ICR-JCL mice, fasted overnight for 17-20 hours. The results were compared with those from rats and mice allowed to feed normally. The order of the fed : fasted ratio of LD50 values in rats was pirenzepin < propantheline < pindolol < salbutamol < orciprenaline < fenoterol < bunitrolol, and was in the range 1·3-4·7. The increased toxicity in fasted animals was considered to be related to acceleration in gastric emptying and intestinal absorption, but not to a general change in the condition of the test system or a decrease in the detoxification ability of the liver because after intraperitoneal administration acute toxicity was similar in fed and fasted rats.