The following adverse reactions have been identified during postapproval 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.
- 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
- Hepatobiliary disorders: Acute liver failure, hepatitis (noninfectious), abnormal liver function test
- Immune system disorders: Hypersensitivity reactions, anaphylactoid reactions, serum sickness, insulin autoimmune syndrome, which can lead to severe hypoglycemia
- Musculoskeletal, connective tissue and bone disorders: Myalgia, arthralgia, arthritis
- Nervous system disorders : Taste disorders, headache, ageusia
- 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
Since clopidogrel is metabolized to its active metabolite partly by CYP2C19, use of drugs that induce the activity of this enzyme would be expected to result in increased drug levels of the active metabolite of clopidogrel.
Rifampin strongly induces CYP2C19 resulting to both an increase level of clopidogrel active metabolite and platelet inhibition, which in particular might potentiate the risk of bleeding. As a precaution, avoid concomitant use of strong CYP2C19 inducers [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3)].
Clopidogrel is metabolized to its active metabolite in part by CYP2C19. Concomitant use of drugs that inhibit the activity of this enzyme results in reduced plasma concentrations of the active metabolite of clopidogrel and a reduction in platelet inhibition [see Warnings and Precautions (5.1)].
Omeprazole or Esomeprazole
Avoid concomitant use of clopidogrel with omeprazole or esomeprazole. In clinical studies, omeprazole was shown to reduce significantly the antiplatelet activity of clopidogrel when given concomitantly or 12 hours apart. A similar reduction in antiplatelet activity was observed with esomeprazole when given concomitantly with clopidogrel. Dexlansoprazole, lansoprazole, and pantoprazole had less effect on the antiplatelet activity of clopidogrel than did omeprazole or esomeprazole [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3)].
As with other oral P2Y12 inhibitors, coadministration of opioid agonists delay and reduce the absorption of clopidogrel, presumably because of slowed gastric emptying, resulting in reduced exposure to its metabolites [see Clinical Pharmacology (12.3)]. Consider the use of a parenteral antiplatelet agent in acute coronary syndrome patients requiring coadministration of morphine or other opioid agonists.
Coadministration of clopidogrel and NSAIDs increases the risk of gastrointestinal bleeding.
Although the administration of clopidogrel 75 mg per day did not modify the pharmacokinetics of S-warfarin (a CYP2C9 substrate) or INR in patients receiving long-term warfarin therapy, coadministration of clopidogrel with warfarin increases the risk of bleeding because of independent effects on hemostasis.
However, at high concentrations in vitr o , clopidogrel inhibits CYP2C9.
Since selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) affect platelet activation, the concomitant administration of SSRIs and SNRIs with clopidogrel may increase the risk of bleeding.
Coadministration of antiplatelet agents increase the risk of bleeding due to an additive effect. Promptly evaluate any signs or symptoms of blood loss if patients are treated concomitantly with other antiplatelet agents [see Warnings and Precautions (5.2)].
The acyl-β-glucuronide metabolite of clopidogrel is a strong inhibitor of CYP2C8. Clopidogrel can increase the systemic exposure to drugs that are primarily cleared by CYP2C8, thereby needing dose adjustment and appropriate monitoring.
Clopidogrel increased repaglinide exposures by 3.9-fold to 5.1-fold [see Clinical Pharmacology (12.3)]. Avoid concomitant use of repaglinide with clopidogrel. If concomitant use cannot be avoided, initiate repaglinide at 0.5 mg before each meal and do not exceed a total daily dose of 4 mg. Increased frequency of glucose monitoring may be required during concomitant use.
Available data from cases reported in published literature and postmarketing surveillance with clopidogrel use in pregnant women have not identified any drug-associated risks for major birth defects or miscarriage [see Data]. There are risks to the pregnant woman and fetus associated with myocardial infarction and stroke [see Clinical Considerations]. No evidence of fetotoxicity was observed when clopidogrel was administered to pregnant rats and rabbits during organogenesis at doses corresponding to 65 and 78 times the recommended daily human dose [see Data].
The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defects, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Disease-associated maternal and/or embryo/fetal risk
Myocardial infarction and stroke are medical emergencies. Therapy for the pregnant woman should not be withheld because of potential concerns regarding the effects of clopidogrel on the fetus.
Labor or delivery
Clopidogrel use during labor or delivery will increase the risk of maternal bleeding and hemorrhage. Avoid neuraxial blockade during clopidogrel use because of the risk of spinal hematoma. When possible, discontinue clopidogrel 5 to 7 days prior to labor, delivery, or neuraxial blockade.
The available data from published case reports over two decades of postmarketing use have not identified an association with clopidogrel use in pregnancy and major birth defects, miscarriage, or adverse fetal outcomes.
Embryo-fetal developmental toxicology studies were performed in pregnant rats and rabbits with doses up to 500 and 300 mg/kg/day, respectively, administered during organogenesis. These doses, corresponding to 65 and 78 times the recommended daily human dose, respectively, on a mg/m2 basis, revealed no evidence of impaired fertility or fetotoxicity due to clopidogrel.
There are no data on the presence of clopidogrel in human milk or the effects on milk production. No adverse effects on breastfed infants have been observed with maternal clopidogrel use during lactation in a small number of postmarketing cases. Studies in rats have shown that clopidogrel and/or its metabolites are present in the milk. When a drug is present in animal milk, it is likely that the drug will be present in human milk. The developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for clopidogrel and any potential adverse effects on the breastfed infant from clopidogrel or from underlying maternal condition.
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