Effect of ethanol dose on its chronopharmacokinetics in the rats.

Circadian changes in the elimination of ethanol after its administration in the rats in two doses: low (1.5 g/kg) and high (4.5 g/kg) were investigated. Circadian rhythm in ethanol pharmacokinetics (AUC, CLpo, t1/2) was observed after the low dose but not after the high one. The maximum rate of elimination was in the dark (active) phase at 1 am. The maximum value of clearance was related to the minimum value of AUC. Although the maximum and the minimum values of Vmax and KM differed essentially the diurnal variation were not observed.