WARNING: DIMINISHED ANTIPLATELET EFFECT IN PATIENTS WITH TWO LOSS-OF-FUNCTION ALLELES OF THE CYP2C19 GENE The effectiveness of clopidogrel results from its antiplatelet activity, which is dependent on its conversion to an active metabolite by the cytochrome P450 (CYP) system, principally CYP2C19 [see Warnings and Precautions (5.1) , Clinical Pharmacology (12.3) ] . Clopidogrel at recommended doses forms less of the active metabolite and so has a reduced effect on platelet activity in patients who are homozygous for nonfunctional alleles of the CYP2C19 gene, (termed “CYP2C19 poor metabolizers”). Tests are available to identify patients who are CYP2C19 poor metabolizers [see Clinical Pharmacology (12.5) ] . Consider use of another platelet P2Y 12 inhibitor in patients identified as CYP2C19 poor metabolizers. WARNING: DIMINISHED ANTIPLATELET EFFECT IN PATIENTS WITH TWO LOSS-OF-FUNCTION ALLELES OF THE CYP2C19 GENE See full prescribing information for complete boxed warning. Effectiveness of clopidogrel depends on conversion to an active metabolite by the cytochrome P450 (CYP) system, principally CYP2C19. ( 5.1 , 12.3 ) Tests are available to identify patients who are CYP2C19 poor metabolizers. (12.5) Consider use of another platelet P2Y 12 inhibitor in patients identified as CYP2C19 poor metabolizers. ( 5.1)
Adult Dosing
General dosing
Acute coronary syndrome – Initiate clopidogrel tablets with a single 300 mg oral loading dose and then continue at 75 mg once daily. – Initiating clopidogrel tablets without a loading dose will delay establishment of an antiplatelet effect by several days. Recent MI, recent stroke, or established peripheral arterial disease: 75 mg once daily orally without a loading dose. 2.1 Acute Coronary Syndrome In patients who need an antiplatelet effect within hours, initiate clopidogrel tablets with a single 300 mg oral loading dose and then continue at 75 mg once daily. Initiating clopidogrel tablets without a loading dose will delay establishment of an antiplatelet effect by several days . 2.2 Recent MI, Recent Stroke, or Established Peripheral Arterial Disease 75 mg once daily orally without a loading dose .
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