Macrolide antibiotics as antiinflammatory agents: roxithromycin in an unexpected role

The antiinflammatory activity of a new 14-membered macrolide antibiotic, roxithromycin, was evaluated in various rat models including carrageenan- and poly-L-arginine-induced hind-paw oedema, croton oil inflamed ear assay and polyester sponge granuloma. When administered orally to animals, roxithromycin displayed an atypical profile in the assays utilized, including: (1) marked antioedema activity similar to that of indomethacin in poly-L-arginine assay, (2) significant inhibition of lambda-carrageenan hind-paw oedema and croton-oil-induced inflammation in the ear, although indomethacin was more effective, and (3) failure to reduce the development of granuloma induced by implanted polyester sponges, while indomethacin significantly reduced the chronic inflammatory reaction. Based on these results, it is concluded that roxithromycin is active in reducing the acute inflammatory reaction in rat models through mechanisms different from conventional nonsteroidal antiinflammatory agents such as indomethacin. Therefore, roxithromycin may have a favorable impact on skin inflammatory reactions accompanying microbial infections.