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Oxymorphone & Concomitant Use with Cytochrome P450 (CYP) Enzyme Inhibitors

    Basic Details
    Last Updated
    Wednesday, September 4, 2019
    Health Outcome(s)
    concomitant use with cytochrome P450 (CYP) enzyme inhibitors
    Drug Use
    Meets requirements of FD&C Act Sec 505(o) prior to requiring a PMR
    Regulatory Determination / Use

    Drug-drug interactions are an important clinical concern. In a March 2017 Advisory Committee, briefing documents raised the possibility that oxymorphone may be used for a particular niche - patients taking multiple medications - because its metabolism did not involve the hepatic cytochrome P450 system. FDA conducted an analysis to assess whether oxymorphone’s metabolism influenced prescriber practices. Results revealed that similar proportions of patients were dispensed oxymorphone combined with other CYP modifiers relative to reference products, suggesting that drug metabolism differences did not influence prescribing behavior.