Therapeutic trials of antibiotic associated colitis.

Since September 1977 we have seen 63 patients with Clostridium difficile and a faecal toxin, but only 33 had histological evidence of pseudomembranous colitis. We have conducted separate double blind trials of an antibiotic, vancomycin and an anion-exchange resin, colestipol, in patients with post-operative diarrhoea. Vancomycin was extremely effective at eradicating the organism and its faecal toxin. These changes were associated with a marked symptomatic improvement. Colestipol proved ineffective in absorbing the faecal toxin and caused no change in numbers of Clostridial difficile. There was no associated symptomatic response. Neither drug had any effect on diarrhoea not related to Clostridium difficile. A carrier state was created by those patients who continued to excrete the organism after Colestipol or placebo treatment. This was eradicated by subsequent treatment with vancomycin. Our brief experience with metronidazole is discussed and a rational basis for treatment advocated.