Tissue penetration and clinical efficacy of enoxacin in respiratory tract infections.

Enoxacin, in common with other new oral 4-quinolones, has a broad spectrum of antimicrobial activity which includes most pulmonary pathogens (with the exception of Streptococcus pneumoniae, against which its activity is poor); this spectrum has provided the impetus for investigation of its potential in the treatment of respiratory infections. Initial pharmacokinetic studies have demonstrated that the drug has a large volume of distribution and achieves concentrations in the secretions of the respiratory tract that are at least as high as those attained in the serum. These concentrations are sufficient to suggest that enoxacin would be effective treatment for most respiratory infections. Furthermore, the concentration of enoxacin that is achieved within the bronchopulmonary tissues is considerably higher than peak serum concentrations and suggests not only that there is an active transport mechanism, but also that the drug could be expected to eradicate organisms in the lungs such as streptococci that are considered moderately sensitive to the drug in vitro. There are relatively few clinical studies of, and thus limited data on, the efficacy of enoxacin in the treatment of respiratory tract infections. A review of the evidence suggests that enoxacin is as successful as other therapies used in the treatment of acute exacerbations of chronic bronchitis. There have sometimes been failures of eradication of, and occasional superinfections with, pneumococci. Enoxacin is also likely to interact with the metabolism of theophylline and so lead to elevated theophylline plasma concentrations. Hence when these 2 agents are given concurrently, careful monitoring of theophylline concentrations and/or dosage adjustments are recommended.(ABSTRACT TRUNCATED AT 250 WORDS)