Résumé
BACKGROUND/AIMThe risk of adverse drug interactions with interferon-α has been poorly assessed. The aim of our study was to establish whether administration of interferon-α at therapeutic doses in patients with chronic hepatitis C may have significant inhibitory effects on other drug metabolism. The study was focused on cytochromes P-450 1A2 and 3A, two major isoforms involved in the metabolism of numerous substrates.
METHODSEighteen patients with chronic active hepatitis C requiring an interferon-α treatment were studied. Cytochrome P-450 1A2 activity was determined on the basis of an in vivo caffeine metabolism study. Cytochrome P-450 3A activity was determined according to in vivo cortisol metabolism into 6-β-hydroxycortisol. Both activities were determined 1 month before, at initiation and 1 month after interferon-α therapy (3 x 10 units, three times a week).
RESULTSThere were no significant differences in the caffeine index (CYP 1A2) and in the 6-β-hydroxycortisol/ free cortisol urinary ratio (CYP 3A) before and after alpha Interferon treatment.
CONCLUSIONChronic administration of interferon-a at therapeutic doses does not change in vivo cytochrome P-450 1A2 and 3A activities. These results support the suggestion that drugs metabolized by these isoenzymes may be used together with interferon-a in patients with chronic hepatitis C without significant risks of drug interactions.