New synthetic quinolone antibacterial agents and serum concentration of theophylline

The effect of pipemidic acid and five new synthetic antibacterial agents--norfloxacin, enoxacin, ofloxacin, ciprofloxacin, and pefloxacin--on the serum level of theophylline was studied in healthy male adult volunteers after concomitant oral administration of these agents with a slow release preparation of theophylline. The results indicated that enoxacin, ciprofloxacin, and pipemidic acid might decrease the clearance of theophylline in the liver, and the attention should be paid in clinical use when enoxacin or pipemidic acid is coadministered with theophylline.