Effects of urea on hexobarbital and antipyrine disposition in rats.

Hexobarbital sleep times, antipyrine-induced temperature depression, in vitro hexobarbital metabolism, and antipyrine half-life were measured in rats receiving either saline or urea pretreatments. Urea pretreatment slows hexobarbital metabolsim and prolongs hexobarbital sleep times. Urea pretreatment als shortens the duration of antipyrine-induced temperature depression as well as the half-life of antipyrine. Urea appears to contribute to the changes in drug metabolism which have been reported for nephrectomized rats, and may also contribute to aberrations of drug metabolism accompanying uremia in man.