Effect of 5-Fluorocytosine and 5-Fluorouracil on Human and Rat Hepatic Cytochrome P 450 Die Wirkung von 5-Fluorcytosin und 5-Fluoruracil auf Leber-Cytochrom-P 450 in Mensch und Ratte

Hepatotoxicity is a well-known side effect of the antifungal drug 5-fluorocytosine. The underlying mechanisms of this toxicity are unknown. The present in vitro study was, therefore, designed to assess the influence of 5-fluorocytosine and 5-fluorouracil on the hepatic cytochrome P 450 concentration in human and rat liver microsomes. Incubation of human or rat hepatic microsomes for 1 h with 5-fluorocytosine up to 500 micrograms/ml or with 5-fluorouracil up to 200 micrograms/ml did not influence the cytochrome P 450 concentration. In comparison the amount of cytochrome P 450 in human liver, however, was lower than in rat liver microsomes and a more interindividual variation was observed.