Caffeine kinetic changes during the oestrous cycle in rats

This study was designed to document possible changes in caffeine kinetics in female rats both according to the stage of the oestrous cycle and in castrated animals. After a single 12 mg/kg ip dose during proestrus, oestrus, dioestrus, or 15 days after castration, the plasmatic clearance of caffeine varied significantly with higher values during oestrous. The other pharmacokinetic parameters did not vary significantly.