ABSENCE OF A PHARMACOKINETIC INTERACTION BETWEEN INTRAVENOUS THEOPHYLLINE AND ORALLY-ADMINISTERED LEVOFLOXACIN

A randomized, placebo-controlled, two-way crossover study in 16 health y men was performed to determine the effect of orally administered lev ofloxacin at steady-state conditions, given at 500 mg every 12 hours, on the pharmacokinetics of theophylline given as a single 4.5-mg/kg in travenous infusion. Participants were assigned randomly to receive the ophylline with levofloxacin in one study period and theophylline with placebo in the other period. Fourteen individuals completed the study. Mean (+/- SD) values for theophylline pharmacokinetic parameters for the levofloxacin and placebo treatments, respectively rt ere peak plas ma concentrations (C-max) of 11.4 (1.8) mu g/mL and 10.7 (1.3) mu g/mL ; areas under the concentration time curve from time 0 extrapolated to infinity (AUC(0-infinity)) of 124 (32) mu g.hr/mL and 126 (30) mu g.h r/mL; volumes of distribution at steady state (Vd(ss)) 31.7 (3.5) L an d 32.0 (3.9) L; clearances (Cl) of 48.6 (11.6) mL/min and 47.4 (10.3) mL/min; and half-lives (t(1/2)), of 8.1 (1.9) hours and 8.2 (1.8) hour s. There were no statistically significant differences between treatme nts for any of these parameters. There It as no pharmacokinetic intera ction between levofloxacin administered orally at steady-state conditi ons and intravenously administered theophylline.