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. Author manuscript; available in PMC: 2013 May 1.
Published in final edited form as: Clin Pharmacol Ther. 2012 May;91(5):774–776. doi: 10.1038/clpt.2012.21

Table 1.

US Food and Drug Administration boxed warning on the clopidogrel (Plavix) product label

WARNING: DIMINISHED EFFECTIVENESS IN POOR METABOLIZERS

  • Effectiveness of Plavix depends on activation to an active metabolite by the cytochrome P450 (CYP) system, principally CYP2C19.

  • Poor metabolizers treated with Plavix at recommended doses exhibit higher cardiovascular event rates following acute coronary syndrome (ACS) or percutaneous coronary intervention (PCI) than patients with normal CYP2C19 function.

  • Tests are available to identify a patient’s CYP2C19 genotype and can be used as an aid in determining therapeutic strategy.

  • Consider alternative treatment or treatment strategies in patients identified as CYP2C19 poor metabolizers.