A Review of Japanese Studies of Roxithromycin

Summary

The pharmacokinetic and microbiological data of roxithromycin, an oral semisynthetic macrolide, and its clinical use in respiratory infections in Japanese patients are reviewed. In healthy men the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of roxithromycin increase with increasing dosage, as does urinary drug excretion. The drug’s C_max and half-life are increased compared with erythromycin, josamycin and miocamycin. Maximum sputum and plasma drug concentrations were higher in patients with chronic bronchitis receiving roxithromycin 150mg than in those receiving erythromycin 400mg. Uptake of roxithromycin into polymorphonuclear cells was proportionally greater than that of erythromycin and josamycin. Roxithromycin showed good in vitro activity against respiratory pathogens, including intracellular pathogens such as Legionella pneumophila and Mycoplasma pneumoniae, although it had only about one-quarter of the activity of erythromycin against Staphylococcus aureus and Streptococcus pneumoniae. High success rates were obtained in patients with acute pneumonia (79%) and chronic obstructive airways disease (75%) receiving roxithromycin in a noncomparative trial in 378 patients with respiratory tract infection, and roxithromycin and miocamycin showed similar efficacy in a double-blind study.

Thus, roxithromycin concentrations achieved in sputum, plasma and intracellularly provide effective antimicrobial activity against respiratory pathogens, and this has been confirmed by the results of clinical trials.