Side effects of rapamycin in the rat.

The side effects of Rapamycin was evaluated by histopathological examination of the heart, kidneys, and eyes of treated Lewis rats. Rapamycin was administered during 14 days by continuous intravenous infusions at doses of 0.5, 1.0, and 1.5 mg/kg/day. Focal myocardial infarction was observed in three of five rats with Rapamycin given at 1.5 mg/kg/day and two of 22 rats with 1.0 mg/kg/day. There were no sign of myocardial toxicity at a Rapamycin dose of 0.5 mg/kg/day. The retina of one eye of a rat treated at a dose of 1.5 mg/kg/day had a small area of focal ischemic necrosis. The kidneys were normal at all doses.