URINE BACTERICIDAL ACTIVITY OF PEFLOXACIN VERSUS NORFLOXACIN IN HEALTHY FEMALE VOLUNTEERS AFTER A SINGLE 800-MG ORAL DOSE

In an open randomised crossover study the antibacterial activity of pe floxacin and norfloxacin was assessed in the urine after a single 800- mg oral dose in 14 healthy female volunteers, Pefloxacin demonstrated lower peak concentrations in the urine than norfloxacin (mean, 217.2 m g/l versus 492.9 mg/l as determined by the microbiological assay) but pefloxacin was present over a longer period of time in sufficient conc entrations than norfloxacin, Mean urine levels of at least 2 mg/l were present for 7 days after pefloxacin administration and 2 days after n orfloxacin administration as determined by the microbiological assay, Overall, the urinary recovery of pefloxacin and norfloxacin amounted t o 49.3% and 25.1%, respectively, of the total administered dose, The a verage urine bactericidal activity against the five test organisms was as follows: against reference strain Escherichia coli ATCC 25922 susc eptible to nalidixic acid (Nal-S) for 5 days with pefloxacin and 2 day s with norfloxacin; against three clinical isolates, one strain each o f E, coli resistant to nalidixic acid (Nal-R), Klebsiella pneumoniae N al-R, and Staphylococcus Saprophyticus, for 3 days with pefloxacin and 24 h with norfloxacin; and against a clinical isolate of Enterococcus faecalis for 2 days with pefloxacin and 12 h with norfloxacin, In con clusion, pefloxacin as a single dose proved to have sufficiently high and long-lasting urine bactericidal activity against urinary pathogens , These findings support the results of a meta-analysis of seven clini cal trials in patients with uncomplicated lower Un, demonstrating a si ngle oral dose of 800 mg pefloxacin to be as effective as a convention al treatment with comparative drugs [21].