Fluoroquinolones.

Since the introduction of the floroquinolones for clinical use in the late 1980s, they have been used successfully for a large number of clinical situations. As experience accumulates, the indications and optimal use of these agents gradually become more clear. Unfortunately, two of the pathogens for which these agents were most promising--methicillin-resistant S. aureus and P. aeruginosa--have developed resistance. Currently, the quinolones are excellent agents for the treatment of complicated urinary tract infections, including those caused by P. aeruginosa. In addition, they should be considered as initial therapy for the treatment of severe bacterial gastroenteritis. The quinolones should also be considered when attempting to eradicate the chronic stool carriage of S. typhi. These agents also offer significant advantages in the treatment of osteomyelitis and prostatitis caused by gram-negative bacilli that frequently require prolonged antimicrobial therapy. Treatment of STDs, especially gonorrhea, is another clear indication for their use. Ciprofloxacin should be considered as initial therapy in patients with malignant otitis externa and in cystic fibrosis patients with exacerbations secondary to P. aeruginosa in the sputum. The role of the quinolones for soft tissue and respiratory tract infections is less clear and their use probably should be limited to certain situations in which there is a clear advantage over beta-lactams, macrolides, and trimethoprim-sulfamethoxazole. The new quinolones, fleroxacin, perfloxacin, sparfloxacin, and tosufloxacin, which are being developed and tested for clinical use, will offer advantages in once-a-day dosing and better gram-positive antimicrobial activity. Because the inappropriate or heavy use of the fluoroquinoles has resulted in considerable development of resistance, it is imperative that they be used only when there is a distinct advantage over conventional therapy in terms of efficacy, safety, or cost. Otherwise, the rapid development of resistance will jeopardize the potentially bright future for this entire class of compounds.