Effects of Escherichia coli lipopolysaccharide on telithromycin pharmacokinetics in rats: inhibition of metabolism via CYP3A.

It has been reported that telithromycin is metabolized primarily via hepatic microsomal cytochrome P450 (CYP) 3A1/2 in rats and that the expression of hepatic and intestinal CYP3A decreases in rats pretreated with Escherichia coli lipopolysaccharide (ECLPS rats; an animal model of inflammation). Thus, it is possible that the area under the plasma concentration-time curve from 0 h to infinity (AUC 0-infinity) of intravenous and oral telithromycin is greater for ECLPS rats than for the controls. To assess this, the pharmacokinetic parameters of telithromycin were compared after intravenous and oral administration (50 mg/kg). After intravenous administration of telithromycin, the AUC 0-infinity was significantly greater (by 83.4%) in ECLPS rats due to a significantly lower nonrenal clearance (by 44.5%) than in the controls. This may have been due to a significantly decreased hepatic metabolism of telithromycin in ECLPS rats. After oral administration of telithromycin, the AUC 0-infinity in ECLPS rats was also significantly greater (by 140%) than in the controls and the increase was considerably greater than the 83.4% increase after intravenous administration. This could have been due to a decrease in intestinal metabolism in addition to a decreased hepatic metabolism of telithromycin in ECLPS rats.