Use of gentamicin to prevent intestinal side effects of lincomycin therapy.

Mild to severe and persisting diarrhea and even colitis have been reported as a side effect of therapy with lincomycin and clindamycin. An alteration in the normal bowel flora with an overgrowth of coliforms and other antibiotic-resistant bacteria has been postulated as a mechanism for the development of diarrhea. Investigations were undertaken in men to observe whether the simultaneous administration of gentamicin was capable of preventing lincomycin-associated intestinal disturbances. Of the 30 subjects treated only with lincomycin 11 (36.6%) developed diarrhea. Of the 18 subjects treated with lincomycin and simultaneously with oral gentamicine, none developed diarrhea. Results of bacteriological examinations indicate that in subjects treated with lincomycin, some potentially pathogenic bacteria, like coliforms and clostridia, are still present in intestinal flora; the simultaneous absence of bifidobacteria and bacteriodes could result in the abolishment of the host resistance to the noxious activity of these endogenous bacteria, as some reported data of the literature suggest. Coliforms and the majority of clostridia strains are not present in subjects treated simultaneously with gentamicin.