CYP3A4/3A5 Inducers

    CYP3A4 and CYP3A5 inducers include, but are not limited to, carbamazepine, dexamethasone, efavirenz, enzalutamide, oxcarbazepine, phenobarbital, phenytoin, prednisone, rifampin, and St. John’s wort. See glossary page for more information.

    Summary

    CYP3A4/3A5 inducers are compounds that increase the activity of the CYP3A4 and CYP3A5 enzymes, which can increase drug metabolism, potentially impacting the effects of drug therapy.

    CYP3A4 is the most abundant cytochrome P450 (CYP) enzyme in the body, and is found primarily in the liver and intestine. It is responsible for the metabolism of any medications that are CYP3A4 substrates, which includes around 50% of drugs.[1] CYP3A4/3A5 inhibitors can increase the body’s metabolism of these medications. CYP3A4 and CYP3A5 are structurally very similar, but CYP3A5 is generally considered to be less metabolically active and is usually present in lower amounts, particularly in people of European descent.[2]

    The table below outlines some of the most common or clinically relevant CYP3A4/3A5 inducers.[2][3][4] Importantly, this list is not exhaustive.

    CYP3A4/5 Inducers
    Carbamazepine
    Dexamethasone
    Efavirenz
    Enzalutamide
    Erlotinib
    Modafinil
    Nevirapine
    Oxcarbazepine
    Phenobarbital
    Phenytoin
    Prednisolone
    Prednisone
    Rifampin
    Ritonavir
    St. John’s wort
    Topiramate

    References

    1. ^Lee SJ, Goldstein JAComparison of CYP3A4 and CYP3A5: the effects of cytochrome b5 and NADPH-cytochrome P450 reductase on testosterone hydroxylation activities.Drug Metab Pharmacokinet.(2012)
    2. ^Song Y, Li C, Liu G, Liu R, Chen Y, Li W, Cao Z, Zhao B, Lu C, Liu YDrug-Metabolizing Cytochrome P450 Enzymes Have Multifarious Influences on Treatment Outcomes.Clin Pharmacokinet.(2021-May)
    3. ^Zanger UM, Schwab MCytochrome P450 enzymes in drug metabolism: regulation of gene expression, enzyme activities, and impact of genetic variation.Pharmacol Ther.(2013-Apr)
    4. ^Hakkola J, Hukkanen J, Turpeinen M, Pelkonen OInhibition and induction of CYP enzymes in humans: an update.Arch Toxicol.(2020-Nov)