Co‐administration of ciprofloxacin and cyclosporin: lack of evidence for a pharmacokinetic interaction.

Abstract

Ciprofloxacin is widely reported to lower theophylline clearance in patients. Since cyclosporin and theophylline are metabolized by cytochrome P-450 enzymes in the human liver, we investigated whether ciprofloxacin could alter the pharmacokinetics of cyclosporin in healthy volunteers. There was no significant difference (P greater than 0.05) in the pharmacokinetic parameters estimated for cyclosporin without and during ciprofloxacin administration. The results of the present study suggest that ciprofloxacin is unlikely to affect the pharmacokinetics of cyclosporin to a clinically important extent at a dosage of 500 mg twice a day.