Pefloxacin in acute exacerbations of chronic bronchitis.

Forty-three patients admitted to hospital with acute purulent exacerbations of chronic bronchitis were treated with 400 mg pefloxacin twice daily for ten days. The first 20 patients were given the first dose of the drug as a 60 min intravenous infusion. Serum and sputum concentrations of pefloxacin were measured microbiologically at intervals on the first treatment day and the sputum was cultured before, during, and after the course of pefloxacin. Two patients died from unrelated causes during the follow-up and one refused to continue treatment. All strains of Haemophilus influenzae and Branhamella catarrhalis were eradicated at end-of-treatment but eight strains of Streptococcus pneumoniae and three of Pseudomonas aeruginosa were cultured and the sputum remained purulent despite the pefloxacin. Peak serum concentrations averaged approximately 4.5 mg/l after the infusion and 5 mg/l on oral administration, the corresponding sputum concentrations being 3.8 and 4.6 mg/l, respectively. MICs for H. influenzae were 0.06 mg/l, or less. Mode MICs for the pre- and post-treatment strains of Str. pneumoniae were 4 and 16 mg/l, and the corresponding values for Ps. aeruginosa were 2 and 16 mg/l. The poor results in pseudomonas and pneumococcal infections could largely be explained by the degree of resistance among these organisms.