Pharmacokinetics and Absolute Oral Bioavailability of an 800-mg Oral Dose of Telithromycin in Healthy Young and Elderly Volunteers

Background: This two-way, randomized, single-dose, crossover study determined the pharmacokinetics and absolute oral bioavailability of telithromycin in young and elderly healthy subjects. Methods: Twelve young (18–40 years) and 12 elderly (>65 years and ≤85 years) subjects received a single 800-mg oral dose of telithromycin or an intravenous infusion of 400 mg (young subjects) or 480 mg (elderly subjects) of telithromycin over 2.5 h in two treatment periods, separated by a 1-week washout period. The plasma concentrations and pharmacokinetic parameters of telithromycin and its major metabolite, RU 76363, were determined. Absolute oral bioavailability was calculated using the area under the plasma concentration-time curve (AUC) from zero hours to infinity. Results: The absolute oral bioavailability of telithromycin was 57% in both young and elderly subjects. The AUC for the metabolite was lower after intravenous infusion of telithromycin, indicating first-pass loss following oral administration. Telithromycin was well tolerated in both groups of subjects. Conclusions: Telithromycin has an absolute oral bioavailability of 57% in young and elderly subjects and is well tolerated.