Importance of cytochrome P450 (CYP450) in adverse drug reactions due to drug-drug interactions: a PharmacoVigilance study in France.

Objective: Our aim was to characterize Adverse Drug Reactions (ADRs) related to drug-drug interactions (DDIs) related to involvement of cytochrome P450 (CYP450) isoenzymes in a pharmacovigilance database. Methods: ADRs recorded by Midi-Pyrénées PharmacoVigilance center (France) between 1 January and 31 August 2008 were extracted from the French PharmacoVigilance Database (FPVD). Results: Among the 1,205 reported ADRs, 16 (1.3 %), can be explained by involvement of CYP450 isoenzymes (including 4 'serious'). All interactions involved CYP inhibitors, mainly for CYP3A4/5. Conclusion: The percentage of ADRs reported in the pharmacovigilance database and related to CYP450-induced DDIs appears to be relatively low (~ 1-2 %). [ABSTRACT FROM AUTHOR]