Analysis of the in vitro interaction between vancomycin and cholestyramine.

Vancomycin and cholestyramine have been utilized both alone and in combination for the treatment of antibiotic-associated pseudomembranous colitis. Previous work for the treatment of antibiotic-associated pseudomembranous colitis. Previous work has demonstrated significant binding of vancomycin by the anion-exchange resin. The antibacterial activity of vancomycin was markedly reduced when the suspension was centrifuged and the supernatant was tested for antibacterial activity. This study confirmed these findings but demonstrated that there was no immediate loss of antibacterial activity of bound vancomycin. The degree of inactivation appeared to be dependent upon the duration of incubation of vancomycin and cholestyramine in the testing system.