1.1 Acute Coronary Syndrome (ACS)

• Plavix is indicated to reduce the rate of myocardial infarction (MI) and stroke in patients with non–ST-segment elevation ACS (unstable angina [UA]/non–ST-elevation myocardial infarction [NSTEMI]), including patients who are to be managed medically and those who are to be managed with coronary revascularization. Plavix should be administered in conjunction with aspirin.
• Plavix is indicated to reduce the rate of myocardial infarction and stroke in patients with acute ST-elevation myocardial infarction (STEMI) who are to be managed medically. Plavix should be administered in conjunction with aspirin.

1.2 Recent MI, Recent Stroke, or Established Peripheral Arterial Disease

In patients with established peripheral arterial disease or with a history of recent myocardial infarction (MI) or recent stroke Plavix is indicated to reduce the rate of MI and stroke.

2.1 Acute Coronary Syndrome

In patients who need an antiplatelet effect within hours, initiate Plavix with a single 300 mg oral loading dose and then continue at 75 mg once daily. Initiating Plavix without a loading dose will delay establishment of an antiplatelet effect by several days [see Clinical Pharmacology (12.3) and Clinical Studies (14.1)].

2.2 Recent MI, Recent Stroke, or Established Peripheral Arterial Disease

75 mg once daily orally without a loading dose [see Clinical Pharmacology (12.3) and Clinical Studies (14.2)].

4.1 Active Bleeding

Plavix is contraindicated in patients with active pathological bleeding such as peptic ulcer or intracranial hemorrhage.

4.2 Hypersensitivity

Plavix is contraindicated in patients with hypersensitivity (e.g., anaphylaxis) to clopidogrel or any component of the product [see Adverse Reactions (6.2)].

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 Plavix with omeprazole or esomeprazole because both significantly reduce the antiplatelet activity of Plavix [see Drug Interactions (7.1)].

5.2 General Risk of Bleeding

P2Y12 inhibitors (thienopyridines), including Plavix, increase the risk of bleeding.

P2Y12 inhibitors (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.

Use of drugs that induce the activity of CYP2C19 would be expected to result in increased drug levels of the active metabolite of clopidogrel and might potentiate the bleeding risk. As a precaution, avoid concomitant use of strong CYP2C19 inducers [see Drug Interactions (7.1) and Clinical Pharmacology (12.3)].

Risk factors for bleeding include concomitant use of other drugs that increase the risk of bleeding (e.g., anticoagulants, antiplatelet agents, and chronic use of NSAIDs) [see Drug Interactions (7.4, 7.5, 7.6, 7.7)].

5.3 Discontinuation of Plavix

Discontinuation of Plavix increases the risk of cardiovascular events. If Plavix 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 Plavix for five days prior to such surgery. Resume Plavix as soon as hemostasis is achieved.

5.4 Thrombotic Thrombocytopenic Purpura (TTP)

TTP, sometimes fatal, has been reported following use of Plavix, 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 has been reported in patients receiving Plavix, including patients with a history of hypersensitivity or hematologic reaction to other thienopyridines [see Contraindications (4.2) and Adverse Reactions (6.2)].

6.1 Clinical Trials 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.

Plavix has 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 Plavix plus aspirin to placebo plus aspirin and trials comparing Plavix alone to aspirin alone are discussed below.

6.2 Postmarketing Experience

The following adverse reactions have been identified during postapproval use of Plavix. 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 Plavix.

• 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

7.1 CYP2C19 Inducers

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)].

7.2 CYP2C19 Inhibitors

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 Plavix with omeprazole or esomeprazole. In clinical studies, omeprazole was shown to reduce significantly the antiplatelet activity of Plavix when given concomitantly or 12 hours apart. A similar reduction in antiplatelet activity was observed with esomeprazole when given concomitantly with Plavix. Dexlansoprazole, lansoprazole, and pantoprazole had less effect on the antiplatelet activity of Plavix than did omeprazole or esomeprazole [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.3)].

7.3 Opioids

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.

7.4 Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Coadministration of Plavix and NSAIDs increases the risk of gastrointestinal bleeding.

7.5 Warfarin (CYP2C9 Substrates)

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 Plavix with warfarin increases the risk of bleeding because of independent effects on hemostasis.

However, at high concentrations in vitro, clopidogrel inhibits CYP2C9.

7.6 SSRIs and SNRIs

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.

7.7 Other Antiplatelet Agents

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)].

7.8 Repaglinide (CYP2C8 Substrates)

The acyl-β-glucuronide metabolite of clopidogrel is a strong inhibitor of CYP2C8. Plavix can increase the systemic exposure to drugs that are primarily cleared by CYP2C8, thereby needing dose adjustment and appropriate monitoring.

Plavix increased repaglinide exposures by 3.9-fold to 5.1-fold [see Clinical Pharmacology (12.3)]. Avoid concomitant use of repaglinide with Plavix. 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.

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

Safety and effectiveness in pediatric populations have not been established.

A randomized, placebo-controlled trial (CLARINET) did not demonstrate a clinical benefit of clopidogrel in neonates and infants with cyanotic congenital heart disease palliated with a systemic-to-pulmonary arterial shunt. Possible factors contributing to this outcome were the dose of clopidogrel, the concomitant administration of aspirin, and the late initiation of therapy following shunt palliation. It cannot be ruled out that a trial with a different design would demonstrate a clinical benefit in this patient population.

8.5 Geriatric Use

Of the total number of subjects in the CAPRIE and CURE controlled clinical studies, approximately 50% of patients treated with Plavix were 65 years of age and older, and 15% were 75 years and older. In COMMIT, approximately 58% of the patients treated with Plavix were 60 years and older, 26% of whom were 70 years and older.

The observed risk of bleeding events with Plavix plus aspirin versus placebo plus aspirin by age category is provided in Table 1 and Table 2 for the CURE and COMMIT trials, respectively [see Adverse Reactions (6.1)]. No dosage adjustment is necessary in elderly patients.

8.6 Renal Impairment

Experience is limited in patients with severe and moderate renal impairment [see Clinical Pharmacology (12.2)].

8.7 Hepatic Impairment

No dosage adjustment is necessary in patients with hepatic impairment [see Clinical Pharmacology (12.2)].

12.1 Mechanism of Action

Clopidogrel is an inhibitor of platelet activation and aggregation through the irreversible binding of its active metabolite to the P2Y12 class of ADP receptors on platelets.

12.2 Pharmacodynamics

Clopidogrel must be metabolized by CYP450 enzymes to produce the active metabolite that inhibits platelet aggregation. The active metabolite of clopidogrel selectively inhibits the binding of adenosine diphosphate (ADP) to its platelet P2Y12 receptor and the subsequent ADP-mediated activation of the glycoprotein GPIIb/IIIa complex, thereby inhibiting platelet aggregation. This action is irreversible. Consequently, platelets exposed to clopidogrel's active metabolite are affected for the remainder of their lifespan (about 7 to 10 days). Platelet aggregation induced by agonists other than ADP is also inhibited by blocking the amplification of platelet activation by released ADP.

Dose-dependent inhibition of platelet aggregation can be seen 2 hours after single oral doses of Plavix. Repeated doses of 75 mg Plavix per day inhibit ADP-induced platelet aggregation on the first day, and inhibition reaches steady state between Day 3 and Day 7. At steady state, the average inhibition level observed with a dose of 75 mg Plavix per day was between 40% and 60%. Platelet aggregation and bleeding time gradually return to baseline values after treatment is discontinued, generally in about 5 days.

12.3 Pharmacokinetics

Clopidogrel is a prodrug and is metabolized to a pharmacologically active metabolite and inactive metabolites.

12.5 Pharmacogenomics

CYP2C19 is involved in the formation of both the active metabolite and the 2-oxo-clopidogrel intermediate metabolite. Clopidogrel active metabolite pharmacokinetics and antiplatelet effects, as measured by ex vivo platelet aggregation assays, differ according to CYP2C19 genotype. Patients who are homozygous for nonfunctional alleles of the CYP2C19 gene are termed "CYP2C19 poor metabolizers." Approximately 2% of White and 4% of Black patients are poor metabolizers; the prevalence of poor metabolism is higher in Asian patients (e.g., 14% of Chinese). Tests are available to identify patients who are CYP2C19 poor metabolizers.

A crossover study in 40 healthy subjects, 10 each in the four CYP2C19 metabolizer groups, evaluated pharmacokinetic and antiplatelet responses using 300 mg followed by 75 mg per day and 600 mg followed by 150 mg per day, each for a total of 5 days. Decreased active metabolite exposure and diminished inhibition of platelet aggregation were observed in the poor metabolizers as compared to the other groups.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

There was no evidence of tumorigenicity when clopidogrel was administered for 78 weeks to mice and 104 weeks to rats at dosages up to 77 mg/kg per day, which afforded plasma exposures >25 times that in humans at the recommended daily dose of 75 mg.

Clopidogrel was not genotoxic in four in vitro tests (Ames test, DNA-repair test in rat hepatocytes, gene mutation assay in Chinese hamster fibroblasts, and metaphase chromosome analysis of human lymphocytes) and in one in vivo test (micronucleus test by oral route in mice).

Clopidogrel was found to have no effect on fertility of male and female rats treated prior to pairing and throughout gestation at oral doses up to 400 mg/kg per day (52 times the recommended human dose on a mg/m2 basis).

14.1 Acute Coronary Syndrome

14.2 Recent Myocardial Infarction, Recent Stroke, or Established Peripheral Arterial Disease

CAPRIE

The CAPRIE trial was a 19,185-patient, 304-center, international, randomized, double-blind, parallel-group study comparing Plavix (75 mg daily) to aspirin (325 mg daily). To be eligible to enroll, patients had to have: 1) recent history of myocardial infarction (within 35 days); 2) recent histories of ischemic stroke (within 6 months) with at least a week of residual neurological signs; and/or 3) established peripheral arterial disease (PAD). Patients received randomized treatment for an average of 1.6 years (maximum of 3 years).

The trial's primary outcome was the time to first occurrence of new ischemic stroke (fatal or not), new myocardial infarction (fatal or not), or other vascular death. Deaths not easily attributable to nonvascular causes were all classified as vascular.

As shown in Table 6, Plavix was associated with a lower incidence of outcome events, primarily MI. The overall relative risk reduction (9.8% vs 10.6%) was 8.7%, p=0.045. Similar results were obtained when all-cause mortality and all-cause strokes were counted instead of vascular mortality and ischemic strokes (risk reduction 6.9%). In patients who survived an on-study stroke or myocardial infarction, the incidence of subsequent events was lower in the Plavix group.

The curves showing the overall event rate are shown in Figure 7. The event curves separated early and continued to diverge over the 3-year follow-up period.

Figure 7: Fatal or Nonfatal Vascular Events in the CAPRIE Study

The statistical significance favoring Plavix over aspirin was marginal (p=0.045). However, because aspirin is itself effective in reducing cardiovascular events in patients with recent myocardial infarction or stroke, the effect of Plavix is substantial.

The CAPRIE trial enrolled a population that had recent MI, recent stroke, or PAD. The efficacy of Plavix relative to aspirin was heterogeneous across these subgroups (p=0.043) (see Figure 8). Nonetheless, this difference may be a chance occurrence because the CAPRIE trial was not designed to evaluate the relative benefit of Plavix over aspirin in the individual patient subgroups. The benefit was most apparent in patients who were enrolled because of peripheral arterial disease and less apparent in stroke patients. In patients who were enrolled in the trial on the sole basis of a recent myocardial infarction, Plavix was not numerically superior to aspirin.

Figure 8: Hazard Ratio and 95% CI by Baseline Subgroups in the CAPRIE Study

14.3 No Demonstrated Benefit of Plavix plus Aspirin in Patients with Multiple Risk Factors or Established Vascular Disease

Store at 25°C (77°F); excursions permitted to 15°C–30°C (59°F–86°F) [see USP Controlled Room Temperature].

Discontinuation

Advise patients not to discontinue Plavix without first discussing it with the healthcare provider who prescribed it [see Warnings and Precautions (5.3)].

Bleeding

Advise patients that they:

• will bruise and bleed more easily
• will take longer than usual to stop bleeding
• must report any unanticipated, prolonged, or excessive bleeding, or blood in their stool or urine [see Warnings and Precautions (5.2)]

Thrombotic Thrombocytopenic Purpura

Instruct patients to get prompt medical attention if they experience symptoms of TTP that cannot otherwise be explained [see Warnings and Precautions (5.4)].

Invasive Procedures

Advise patients to inform physicians and dentists that they are taking Plavix before any surgery or dental procedure [see Warnings and Precautions (5.2, 5.3)].

Proton Pump Inhibitors

Advise patients not to take omeprazole or esomeprazole while taking Plavix. Dexlansoprazole, lansoprazole, and pantoprazole had less pronounced effects on the antiplatelet activity of Plavix than did omeprazole or esomeprazole [see Drug Interactions (7.1)].