Do we need an intravenous fluoroquinolone?

Intravenous ciprofloxacin, the first parenteral fluoroquinolone available in this country, represents another class of antimicrobial agents from which physicians must choose when treating nosocomial infections. Fluoroquinolones are bactericidal antimicrobial agents that act by inhibiting DNA gyrase. They are active in vitro against most gram-negative bacteria and methicillin-susceptible staphylococci. Activity against anaerobic bacteria and streptococci is poor. The rapid development of bacterial resistance in centers with high quinolone usage is of great concern. Resistance develops most commonly in Pseudomonas aeruginosa and staphylococci. Resistance emerges most often when quinolones are used to treat chronic infections or in patients with poorly drained abscesses, necrotic tissue, or indwelling catheters. Clinical trials have shown ciprofloxacin to be as effective as ceftazidime in the treatment of infections caused by gram-negative bacteria. Although the overall frequency of side effects to fluoroquinolones is low, seizures and allergic reactions have been attributed to their use. Ciprofloxacin inhibits the metabolism of theophylline, and morbidity and death have been reported in patients taking the two drugs concomitantly. Parenteral fluoroquinolones should be reserved for the treatment of gram-negative bacterial infections in patients in whom standard agents cannot be used.