LEVOFLOXACIN DOES NOT ALTER CYCLOSPORINE DISPOSITION

Certain fluoroquinolones have been shown to elevate the serum concentr ations of the immunosuppressant cyclosporine. It is th us important to investigate the potential interaction between levofloxacin, a new flu oroquinolone anitmicrobial agent, and the pharmacokinetics of cyclospo rine. Twelve healthy subjects (6 men, 6 women) were enrolled in and co mpleted a placebo-controlled, randomized, double-blind, two-phase cros sover study. Subjects were given a single oral 10-mg/kg dose of cyclos porine solution during multiple-dose twice-daily oral treatment with p lacebo or 500 mg of levofloxacin. Blood cyclosporine concentrations we re measured for 48 hours after each cyclosporine dose for pharmacokine tic evaluation. Cyclosporine pharmacokinetic parameters were comparabl e and not significantly different in the absence and presence of levof loxacin. Results of this study suggest that a clinically important pha rmacokinetic interaction between levofloxacin and cyclosporine is unli kely to occur during concurrent therapy.