The multiple-dose pharmacokinetics and safety of amifloxacin, a new fluoroquinolone antibacterial agent, were evaluated in healthy male volunteers. Amifloxacin was administered orally at 200, 400, or 600 mg every 12 h (q12h) and 400, 600, or 800 mg every 8 h (q8h) for 10 days. An additional dose was administered on day 11. Clinically significant adverse reactions, including pruritus and transaminase elevations, occurred only at doses of 1200 mg/day or above.

The activity of amifloxacin, a new quinolone carboxylic acid compound, against 147 strains of microorganisms was studied and was compared with the activities of cinoxacin, trimethoprim, amikacin, and four beta-lactam antimicrobials. The minimal concentration at which 90% of strains were inhibited by amifloxacin was lowest for Escherichia coli and Klebsiella sp (less than or equal to 0.125 ug/ml), followed by Proteus sp (less than or equal to 0.25 ug/ml), Enterobacter sp and Citrobacter sp (less than or equal to 0.5 ug/ml), Providencia sp (less than or equal to 2 ug/ml), and Pseudomonas aeruginosa, Serratia sp, and Acinetobacter calcoaceticus var anitratus (less than or equal to 8 ug/ml). For amikacin-resistant P aeruginosa, the minimal inhibitory concentrations (MICs) of amifloxacin ranged from 1 to 16 ug/ml.