Effect of fasting on the toxicity and serum concentration of aminopyrine in rats.

Effect of Fasting on the Toxicity and Serum Concentration of Aminopyrine in Rats. CORNISH, HERBERT H., MORRISON, A. B., and NELSON, JOHN M. (1970). Toxicol. Appl. Pharmacol. 17,217-222. The acute oral toxicity of aminopyrine is considerably greater in the fasted rat than in the fed rat. Acute toxicity by the ip route was comparable in these two groups of animals. Serum aminopyrine concentrations in the fasted rat reached maximum values within 5 min after oral dosing compared with approximately 15 min after dosing in the fed (ad libitum) animals. Maximum serum aminopyrine concentrations in the fasted rats were more than double those of the fed animals, thus accounting for the increased acute toxicity of this compound in fasted animals. These data not only indicate the importance of serum concentrations in toxicity studies, but also emphasize the necessity for consideration of the short-term nutritional status of the animals used in toxicologic investigations.