Methadone metabolism and cytochrome P450 polymorphisms: a systematic review and meta-analysis.

Introduction: Confusion regarding methadone metabolism exists, hampering optimal clinical use. A systematic review was conducted to assess the impacts of cytochrome P450 (CYP) genetic polymorphisms on methadone outcomes.

Methods: MEDLINE, EMBASE, Web of Science, PsycINFO, and CENTRAL were searched to identify studies reporting methadone dose-adjusted plasma concentrations, clearance, maintenance dose, or treatment response in relation to polymorphisms in humans.