WARNING: DIMINISHED ANTIPLATELET EFFECT IN PATIENTS WITH TWO LOSS-OF-FUNCTION ALLELES OF THE CYP2C19 GENE The effectiveness of clopidogrel tablets 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 tablets at recommended doses form 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 P2Y12 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 tablets 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 P2Y12 inhibitor in patients identified as CYP2C19 poor metabolizers. ( 5.1 )
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warnings and cautions
5 WARNINGS AND PRECAUTIONS CYP2C19 inhibitors: Avoid concomitant use of omeprazole or esomeprazole. ( 5.1 ) Bleeding: Clopidogrel tablets increase risk of bleeding. ( 5.2 ) Discontinuation: Premature discontinuation increases risk of cardiovascular events. Discontinue 5 days prior to elective surgery that has a major risk of bleeding. ( 5.3 ) Thrombotic thrombocytopenic purpura (TTP) has been reported. ( 5.4 ) Cross-reactivity among thienopyridines has been reported. ( 5.5 ) 5.1 Diminished Antiplatelet Activity in Patients with Impaired CYP2C19 Function Clopidogrel is a prodrug. Inhibition of platelet aggregation by clopidogrel is achieved through an active metabolite. The metabolism of clopidogrel to its active metabolite can be impaired by genetic variations in CYP2C19 [see Boxed Warning ] . The metabolism of clopidogrel can also be impaired by drugs that inhibit CYP2C19, such as omeprazole or esomeprazole. Avoid concomitant use of clopidogrel tablets with omeprazole or esomeprazole because both significantly reduce the antiplatelet activity of clopidogrel tablets [see Drug Interactions (7.1) ] . 5.2 General Risk of Bleeding Thienopyridines, including clopidogrel tablets, increase the risk of bleeding. Thienopyridines inhibit platelet aggregation for the lifetime of the platelet (7-10 days). Because the half-life of clopidogrel’s active metabolite is short, it may be possible to restore hemostasis by administering exogenous platelets; however, platelet transfusions within 4 hours of the loading dose or 2 hours of the maintenance dose may be less effective. 5.3 Discontinuation of Clopidogrel Tablets Discontinuation of clopidogrel tablets increases the risk of cardiovascular events. If clopidogrel tablets must be temporarily discontinued (e.g., to treat bleeding or for surgery with a major risk of bleeding), restart it as soon as possible. When possible, interrupt therapy with clopidogrel tablets for five days prior to such surgery. Resume clopidogrel tablets as soon as hemostasis is achieved. 5.4 Thrombotic Thrombocytopenic Purpura (TTP) TTP, sometimes fatal, has been reported following use of clopidogrel tablets, sometimes after a short exposure (< 2 weeks). TTP is a serious condition that requires urgent treatment including plasmapheresis (plasma exchange). It is characterized by thrombocytopenia, microangiopathic hemolytic anemia (schistocytes [fragmented RBCs] seen on peripheral smear), neurological findings, renal dysfunction, and fever [see Adverse Reactions (6.2) ] . 5.5 Cross-Reactivity among Thienopyridines Hypersensitivity including rash, angioedema or hematologic reaction have been reported in patients receiving clopidogrel tablets, including patients with a history of hypersensitivity or hematologic reaction to other thienopyridines [see Contraindications (4.2) and Adverse Reactions (6.2) ] .
6 ADVERSE REACTIONS The following serious adverse reactions are discussed below and elsewhere in the labeling: Bleeding [see Warnings and Precautions (5.2) ] Thrombotic thrombocytopenic purpura [see Warnings and Precautions (5.4) ] Bleeding, including life-threatening and fatal bleeding, is the most commonly reported adverse reaction. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Mylan Pharmaceuticals Inc. at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions and durations of follow up, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Clopidogrel tablets have been evaluated for safety in more than 54,000 patients, including over 21,000 patients treated for one year or more. The clinically important adverse reactions observed in trials comparing clopidogrel tablets plus aspirin to placebo plus aspirin and trials comparing clopidogrel tablets alone to aspirin alone are discussed below. Bleeding CURE In CURE, clopidogrel tablets use with aspirin was associated with an increase in major bleeding (primarily gastrointestinal and at puncture sites) compared to placebo with aspirin (see Table 1). The incidence of intracranial hemorrhage (0.1%) and fatal bleeding (0.2%) were the same in both groups. Other bleeding events that were reported more frequently in the clopidogrel group were epistaxis, hematuria, and bruise. The overall incidence of bleeding is described in Table 1. Table 1: CURE Incidence of Bleeding Complications (% Patients) Event Clopidogrel Tablets (+ aspirin) (n = 6259) Placebo (+ aspirin) (n = 6303) Major bleeding Life-threatening and other major bleeding. 3.7 2.7 Life-threatening bleeding 2.2 1.8 Fatal 0.2 0.2 5 g/dL hemoglobin drop 0.9 0.9 Requiring surgical intervention 0.7 0.7 Hemorrhagic strokes 0.1 0.1 Requiring inotropes 0.5 0.5 Requiring transfusion (≥ 4 units) 1.2 1.0 Other major bleeding 1.6 1.0 Significantly disabling 0.4 0.3 Intraocular bleeding with significant loss of vision 0.05 0.03 Requiring 2-3 units of blood 1.3 0.9 Minor bleeding Led to interruption of study medication. 5.1 2.4 COMMIT In COMMIT, similar rates of major bleeding were observed in the clopidogrel tablets and placebo groups, both of which also received aspirin (see Table 2). Table 2: Incidence of Bleeding Events in COMMIT (% Patients) Type of bleeding Clopidogrel Tablets (+ aspirin) (n = 22961) Placebo (+ aspirin) (n = 22891) p-value Major Major bleeds were cerebral bleeds or noncerebral bleeds thought to have caused death or that required transfusion. noncerebral or cerebral bleeding Major noncerebral Fatal Hemorrhagic stroke Fatal 0.6 0.4 0.2 0.2 0.2 0.5 0.3 0.2 0.2 0.2 0.59 0.48 0.90 0.91 0.81 Other noncerebral bleeding (non-major) 3.6 3.1 0.005 Any noncerebral bleeding 3.9 3.4 0.004 CAPRIE (Clopidogrel Tablets vs. Aspirin) In CAPRIE, gastrointestinal hemorrhage occurred at a rate of 2.0% in those taking clopidogrel tablets vs. 2.7% in those taking aspirin; bleeding requiring hospitalization occurred in 0.7% and 1.1%, respectively. The incidence of intracranial hemorrhage was 0.4% for clopidogrel tablets compared to 0.5% for aspirin. Other bleeding events that were reported more frequently in the clopidogrel tablets group were epistaxis and hematoma. Other Adverse Events In CURE and CHARISMA, which compared clopidogrel tablets plus aspirin to aspirin alone, there was no difference in the rate of adverse events (other than bleeding) between clopidogrel tablets and placebo. In CAPRIE, which compared clopidogrel tablets to aspirin, pruritus was more frequently reported in those taking clopidogrel tablets. No other difference in the rate of adverse events (other than bleeding) was reported. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of clopidogrel tablets. Because these reactions are reported voluntarily from a population of an unknown size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Hemorrhages, including those with fatal outcome, have been reported in patients treated with clopidogrel tablets. Blood and Lymphatic System Disorders: Agranulocytosis, aplastic anemia/pancytopenia, thrombotic thrombocytopenic purpura (TTP), acquired hemophilia A Gastrointestinal Disorders: Colitis (including ulcerative or lymphocytic colitis), pancreatitis, stomatitis, gastric/duodenal ulcer, diarrhea General Disorders and Administration Site Condition: Fever Hepato-Biliary Disorders: Acute liver failure, hepatitis (non-infectious), abnormal liver function test Immune System Disorders: Hypersensitivity reactions, anaphylactoid reactions, serum sickness Musculoskeletal, Connective Tissue and Bone Disorders: Myalgia, arthralgia, arthritis Nervous System Disorders: Taste disorders, headache Psychiatric Disorders: Confusion, hallucinations Respiratory, Thoracic and Mediastinal Disorders: Bronchospasm, interstitial pneumonitis, eosinophilic pneumonia Renal and Urinary Disorders: Increased creatinine levels Skin and Subcutaneous Tissue Disorders: Maculopapular, erythematous or exfoliative rash, urticaria, bullous dermatitis, eczema, toxic epidermal necrolysis, Stevens-Johnson Syndrome, acute generalized exanthematous pustulosis (AGEP), angioedema, drug-induced hypersensitivity syndrome, drug rash with eosinophilia and systemic symptoms (DRESS), erythema multiforme, lichen planus, generalized pruritus Vascular Disorders: Vasculitis, hypotension