About This Medication
11 DESCRIPTION Prasugrel tablets USP contain prasugrel, a thienopyridine class inhibitor of platelet activation and aggregation mediated by the P2Y 12 ADP receptor. Prasugrel is formulated as the hydrochloride salt, a racemate, which is chemically designated as 5-[(1RS)-2-cyclopropyl-1-(2-fluorophenyl)-2-oxoethyl]-4,5,6,7-tetrahydrothieno[3,2-c]pyridin-2-yl acetate hydrochloride. Prasugrel hydrochloride USP has the molecular formula C 20 H 20 FNO 3 S•HCl representing a molecular weight of 409.90. The chemical structure of prasugrel hydrochloride USP is: Prasugrel hydrochloride USP is a white to practically white powder. It is freely soluble in methanol, practically insoluble in water. Prasugrel tablets USP are available for oral administration as 5 mg or 10 mg elongated hexagonal, film-coated, non-scored tablets, debossed on each side. Each yellow 5 mg tablet is manufactured with 5.49 mg prasugrel hydrochloride USP, equivalent to 5 mg prasugrel and each beige 10 mg tablet with 10.98 mg prasugrel hydrochloride USP, equivalent to 10 mg of prasugrel. Other ingredients include glyceryl dibehenate, hypromellose, lactose monohydrate, low substituted hydroxypropyl cellulose, mannitol, microcrystalline cellulose, sucrose stearate, titanium dioxide, triacetin, and yellow iron oxide. In addition, the 10 mg tablets contain red iron oxide. Chemical Structure
有効成分
| 成分 |
含有量 |
| Prasugrel Hydrochloride |
- |
適応症と用法
1 INDICATIONS AND USAGE Prasugrel tablets are a P2Y 12 platelet inhibitor indicated for the reduction of thrombotic cardiovascular events (including stent thrombosis) in patients with acute coronary syndrome who are to be managed with percutaneous coronary intervention (PCI) as follows: Patients with unstable angina or non-ST-elevation myocardial infarction (NSTEMI) (1.1) . Patients with ST-elevation myocardial infarction (STEMI) when managed with either primary or delayed PCI (1.1) . 1.1 Acute Coronary Syndrome Prasugrel tablets are indicated to reduce the rate of thrombotic CV events (including stent thrombosis) in patients with acute coronary syndrome (ACS) who are to be managed with percutaneous coronary intervention (PCI) as follows: Patients with unstable angina (UA) or non-ST-elevation myocardial infarction (NSTEMI). Patients with ST-elevation myocardial infarction (STEMI) when managed with primary or delayed PCI. Prasugrel tablets have been shown to reduce the rate of a combined endpoint of cardiovascular death, nonfatal myocardial infarction (MI), or nonfatal stroke compared to clopidogrel. The difference between treatments was driven predominantly by MI, with no difference on strokes and little difference on CV death [see Clinical Studies (14) ] .
作用のしくみ
12.1 Mechanism of Action Prasugrel is an inhibitor of platelet activation and aggregation through the irreversible binding of its active metabolite to the P2Y 12 class of ADP receptors on platelets.
用量と投与方法
2 DOSAGE AND ADMINISTRATION Initiate prasugrel tablets treatment as a single 60 mg oral loading dose and then continue at 10 mg orally once daily. Patients taking prasugrel tablets should also take aspirin (75 mg to 325 mg) daily [see Drug Interactions (7.4) and Clinical Pharmacology (12.3) ] . Prasugrel tablets may be administered with or without food [see Clinical Pharmacology (12.3) and Clinical Studies (14) ] . Timing of Loading Dose In the clinical trial that established the efficacy and safety of prasugrel tablets, the loading dose of prasugrel tablets was not administered until coronary anatomy was established in UA/NSTEMI patients and in STEMI patients presenting more than 12 hours after symptom onset. In STEMI patients presenting within 12 hours of symptom onset, the loading dose of prasugrel tablets was administered at the time of diagnosis, although most received prasugrel tablets at the time of PCI [see Clinical Studies (14) ] . For the small fraction of patients that required urgent CABG after treatment with prasugrel tablets, the risk of significant bleeding was substantial. Although it is generally recommended that antiplatelet therapy be administered promptly in the management of ACS because many cardiovascular events occur within hours of initial presentation, in a trial of 4033 NSTEMI patients, no clear benefit was observed when prasugrel tablets loading dose was administered prior to diagnostic coronary angiography compared to at the time of PCI; however, risk of bleeding was increased with early administration in patients undergoing PCI or early CABG. Dosing in Low Weight Patients Compared to patients weighing ≥60 kg, patients weighing <60 kg have an increased exposure to the active metabolite of prasugrel and an increased risk of bleeding on a 10 mg once daily maintenance dose. Consider lowering the maintenance dose to 5 mg in patients <60 kg. The effectiveness and safety of the 5 mg dose have not been prospectively studied [see Warnings and Precautions (5.1) , Adverse Reactions (6.1) , and Clinical Pharmacology (12.3) ] . Initiate treatment with a single 60 mg oral loading dose (2) . Continue at 10 mg once daily with or without food. Consider 5 mg once daily for patients <60 kg (2) . Patients should also take aspirin (75 mg to 325 mg) daily (2) .
Side Effects Overview
6 ADVERSE REACTIONS The following serious adverse reactions are also discussed elsewhere in the labeling: Bleeding [see Boxed Warning and Warnings and Precautions (5.1 , 5.2) ] Thrombotic Thrombocytopenic Purpura [see Warnings and Precautions (5.4) ] Hypersensitivity Including Angioedema [see Warnings and Precautions (5.5) ] Bleeding, including life-threatening and fatal bleeding, is the most commonly reported adverse reaction (6.1) . To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Safety in patients with ACS undergoing PCI was evaluated in a clopidogrel-controlled study, TRITON-TIMI 38, in which 6741 patients were treated with prasugrel (60 mg loading dose and 10 mg once daily) for a median of 14.5 months (5802 patients were treated for over 6 months; 4136 patients were treated for more than 1 year). The population treated with prasugrel was 27 to 96 years of age, 25% female, and 92% Caucasian. All patients in the TRITON-TIMI 38 study were to receive aspirin. The dose of clopidogrel in this study was a 300 mg loading dose and 75 mg once daily. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with the rates observed in other clinical trials of another drug and may not reflect the rates observed in practice. Drug Discontinuation The rate of study drug discontinuation because of adverse reactions was 7.2% for prasugrel and 6.3% for clopidogrel. Bleeding was the most common adverse reaction leading to study drug discontinuation for both drugs (2.5% for prasugrel and 1.4% for clopidogrel). Bleeding Bleeding Unrelated to CABG Surgery In TRITON-TIMI 38, overall rates of TIMI Major or Minor bleeding adverse reactions unrelated to coronary artery bypass graft surgery (CABG) were significantly higher on prasugrel than on clopidogrel, as shown in Table 1. Table 1: Non-CABG-Related Bleeding Patients may be counted in more than one row. (TRITON-TIMI 38) Prasugrel (%) (N=6741) Clopidogrel (%) (N=6716) TIMI Major or Minor bleeding 4.5 3.4 TIMI Major bleeding See 5.1 for definition. 2.2 1.7 Life-threatening 1.3 0.8 Fatal 0.3 0.1 Symptomatic intracranial hemorrhage (ICH) 0.3 0.3 Requiring inotropes 0.3 0.1 Requiring surgical intervention 0.3 0.3 Requiring transfusion (≥4 units) 0.7 0.5 TIMI Minor bleeding 2.4 1.9 Figure 1 demonstrates non-CABG-related TIMI Major or Minor bleeding. The bleeding rate is highest initially, as shown in Figure 1 (inset: Days 0 to 7) [see Warnings and Precautions (5.1) ] . Bleeding by Weight and Age In TRITON-TIMI 38, non-CABG-related TIMI Major or Minor bleeding rates in patients with the risk factors of age ≥75 years and weight <60 kg are shown in Table 2. Table 2: Bleeding Rates for Non-CABG-Related Bleeding by Weight and Age (TRITON-TIMI 38) Major/Minor Fatal Prasugrel (%) 10 mg prasugrel maintenance dose Clopidogrel 75 mg clopidogrel maintenance dose (%) Prasugrel (%) Clopidogrel (%) Weight <60 kg (N=308 prasugrel, N=356 clopidogrel) 10.1 6.5 0.0 0.3 Weight ≥60 kg (N=6373 prasugrel, N=6299 clopidogrel) 4.2 3.3 0.3 0.1 Age <75 years (N=5850 prasugrel, N=5822 clopidogrel) 3.8 2.9 0.2 0.1 Age ≥75 years (N=891 prasugrel, N=894 clopidogrel) 9.0 6.9 1.0 0.1 Bleeding Related to CABG In TRITON-TIMI 38, 437 patients who received a thienopyridine underwent CABG during the course of the study. The rate of CABG-related TIMI Major or Minor bleeding was 14.1% for the prasugrel group and 4.5% in the clopidogrel group (see Table 3). The higher risk for bleeding adverse reactions in patients treated with prasugrel persisted up to 7 days from the most recent dose of study drug. Table 3: CABG-Related Bleeding Patients may be counted in more than one row. (TRITON-TIMI 38) Prasugrel (%) (N=213) Clopidogrel (%) (N=224) TIMI Major or Minor bleeding 14.1 4.5 TIMI Major bleeding 11.3 3.6 Fatal 0.9 0 Reoperation 3.8 0.5 Transfusion of ≥5 units 6.6 2.2 Intracranial hemorrhage 0 0 TIMI Minor bleeding 2.8 0.9 Bleeding Reported as Adverse Reactions Hemorrhagic events reported as adverse reactions in TRITON-TIMI 38 were, for prasugrel and clopidogrel, respectively: epistaxis (6.2%, 3.3%), gastrointestinal hemorrhage (1.5%, 1.0%), hemoptysis (0.6%, 0.5%), subcutaneous hematoma (0.5%, 0.2%), post-procedural hemorrhage (0.5%, 0.2%), retroperitoneal hemorrhage (0.3%, 0.2%), pericardial effusion/hemorrhage/tamponade (0.3%, 0.2%), and retinal hemorrhage (0.0%, 0.1%). Malignancies During TRITON-TIMI 38, newly diagnosed malignancies were reported in 1.6% and 1.2% of patients treated with prasugrel and clopidogrel, respectively. The sites contributing to the differences were primarily colon and lung. In another Phase 3 clinical study of ACS patients not undergoing PCI, in which data for malignancies were prospectively collected, newly diagnosed malignancies were reported in 1.8% and 1.7% of patients treated with prasugrel and clopidogrel, respectively. The site of malignancies was balanced between treatment groups except for colorectal malignancies. The rates of colorectal malignancies were 0.3% prasugrel, 0.1% clopidogrel and most were detected during investigation of GI bleed or anemia. It is unclear if these observations are causally related, are the result of increased detection because of bleeding, or are random occurrences. Other Adverse Events In TRITON-TIMI 38, common and other important nonhemorrhagic adverse events were, for prasugrel and clopidogrel, respectively: severe thrombocytopenia (0.06%, 0.04%), anemia (2.2%, 2.0%), abnormal hepatic function (0.22%, 0.27%), allergic reactions (0.36%, 0.36%), and angioedema (0.06%, 0.04%). Table 4 summarizes the adverse events reported by at least 2.5% of patients. Table 4: Non-Hemorrhagic Treatment Emergent Adverse Events Reported by at Least 2.5% of Patients in Either Group Prasugrel (%) (N=6741) Clopidogrel (%) (N=6716) Hypertension 7.5 7.1 Hypercholesterolemia/Hyperlipidemia 7.0 7.4 Headache 5.5 5.3 Back pain 5.0 4.5 Dyspnea 4.9 4.5 Nausea 4.6 4.3 Dizziness 4.1 4.6 Cough 3.9 4.1 Hypotension 3.9 3.8 Fatigue 3.7 4.8 Noncardiac chest pain 3.1 3.5 Atrial fibrillation 2.9 3.1 Bradycardia 2.9 2.4 Leukopenia (<4 x 10 9 WBC WBC = white blood cell /L) 2.8 3.5 Rash 2.8 2.4 Pyrexia 2.7 2.2 Peripheral edema 2.7 3.0 Pain in extremity 2.6 2.6 Diarrhea 2.3 2.6 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of prasugrel. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and lymphatic system disorders — thrombocytopenia, thrombotic thrombocytopenic purpura (TTP) [see Warnings and Precautions (5.4) and Patient Counseling Information (17) ] Immune system disorders — hypersensitivity reactions including anaphylaxis [see Contraindications (4.3) ]
警告と注意事項
5 WARNINGS AND PRECAUTIONS CABG-related bleeding: Risk increases in patients receiving prasugrel who undergo CABG (5.2) . Discontinuation of Prasugrel: Premature discontinuation increases risk of stent thrombosis, MI, and death (5.3) . Thrombotic thrombocytopenic purpura (TTP): TTP has been reported with prasugrel (5.4) . Hypersensitivity: Hypersensitivity including angioedema has been reported with prasugrel including in patients with a history of hypersensitivity reaction to other thienopyridines (5.5) . 5.1 General Risk of Bleeding Thienopyridines, including prasugrel, increase the risk of bleeding. With the dosing regimens used in TRITON-TIMI 38, TIMI (Thrombolysis in Myocardial Infarction) Major (clinically overt bleeding associated with a fall in hemoglobin ≥5 g/dL, or intracranial hemorrhage) and TIMI Minor (overt bleeding associated with a fall in hemoglobin of ≥3 g/dL but <5 g/dL), bleeding events were more common on prasugrel than on clopidogrel [see Adverse Reactions (6.1) ] . The bleeding risk is highest initially, as shown in Figure 1 (events through 450 days; inset shows events through 7 days). Figure 1: Non-CABG-Related TIMI Major or Minor Bleeding Events Suspect bleeding in any patient who is hypotensive and has recently undergone coronary angiography, PCI, CABG, or other surgical procedures even if the patient does not have overt signs of bleeding. Do not use prasugrel in patients with active bleeding, prior TIA or stroke [see Contraindications (4.1 , 4.2) ] . Other risk factors for bleeding are: Age ≥75 years. Because of the risk of bleeding (including fatal bleeding) and uncertain effectiveness in patients ≥75 years of age, use of prasugrel is generally not recommended in these patients, except in high-risk situations (patients with diabetes or history of myocardial infarction) where its effect appears to be greater and its use may be considered [see Adverse Reactions (6.1) , Use in Specific Populations (8.5) , Clinical Pharmacology (12.3) , and Clinical Studies (14) ] . CABG or other surgical procedure [see Warnings and Precautions (5.2) ] . Body weight <60 kg. Consider a lower (5 mg) maintenance dose [see Dosage and Administration (2) , Adverse Reactions (6.1) , and Use in Specific Populations (8.6) ] . Propensity to bleed (e.g., recent trauma, recent surgery, recent or recurrent gastrointestinal (GI) bleeding, active peptic ulcer disease, severe hepatic impairment, or moderate to severe renal impairment) [see Adverse Reactions (6.1) and Use in Specific Populations (8.7 , 8.8) ] . Medications that increase the risk of bleeding (e.g., oral anticoagulants, chronic use of nonsteroidal anti-inflammatory drugs [NSAIDs], and fibrinolytic agents). Aspirin and heparin were commonly used in TRITON-TIMI 38 [see Drug Interactions (7.1 , 7.2 , 7.4 ) and Clinical Studies (14) ] . Thienopyridines inhibit platelet aggregation for the lifetime of the platelet (7 to 10 days), so withholding a dose will not be useful in managing a bleeding event or the risk of bleeding associated with an invasive procedure. Because the half-life of prasugrel’s active metabolite is short relative to the lifetime of the platelet, it may be possible to restore hemostasis by administering exogenous platelets; however, platelet transfusions within 6 hours of the loading dose or 4 hours of the maintenance dose may be less effective. Figure 1: Non-CABG-Related TIMI Major or Minor Bleeding Events. 5.2 Coronary Artery Bypass Graft Surgery-Related Bleeding The risk of bleeding is increased in patients receiving prasugrel who undergo CABG. If possible, prasugrel should be discontinued at least 7 days prior to CABG. Of the 437 patients who underwent CABG during TRITON-TIMI 38, the rates of CABG-related TIMI Major or Minor bleeding were 14.1% in the prasugrel group and 4.5% in the clopidogrel group [see Adverse Reactions (6.1) ] . The higher risk for bleeding events in patients treated with prasugrel persisted up to 7 days from the most recent dose of study drug. For patients receiving a thienopyridine within 3 days prior to CABG, the frequencies of TIMI Major or Minor bleeding were 26.7% (12 of 45 patients) in the prasugrel group, compared with 5.0% (3 of 60 patients) in the clopidogrel group. For patients who received their last dose of thienopyridine within 4 to 7 days prior to CABG, the frequencies decreased to 11.3% (9 of 80 patients) in the prasugrel group and 3.4% (3 of 89 patients) in the clopidogrel group. Do not start prasugrel in patients likely to undergo urgent CABG. CABG-related bleeding may be treated with transfusion of blood products, including packed red blood cells and platelets; however, platelet transfusions within 6 hours of the loading dose or 4 hours of the maintenance dose may be less effective. 5.3 Discontinuation of Prasugrel Discontinue thienopyridines, including prasugrel, for active bleeding, elective surgery, stroke, or TIA. The optimal duration of thienopyridine therapy is unknown. In patients who are managed with PCI and stent placement, premature discontinuation of any antiplatelet medication, including thienopyridines, conveys an increased risk of stent thrombosis, myocardial infarction, and death. Patients who require premature discontinuation of a thienopyridine will be at increased risk for cardiac events. Lapses in therapy should be avoided, and if thienopyridines must be temporarily discontinued because of an adverse event(s), they should be restarted as soon as possible [see Contraindications (4.1 , 4.2) and Warnings and Precautions (5.1) ] . 5.4 Thrombotic Thrombocytopenic Purpura (TTP) TTP has been reported with the use of prasugrel. TTP can occur after a brief exposure (<2 weeks). TTP is a serious condition that can be fatal and requires urgent treatment, including plasmapheresis (plasma exchange). TTP is characterized by thrombocytopenia, microangiopathic hemolytic anemia (schistocytes [fragment red blood cells] seen on peripheral smear), neurological findings, renal dysfunction, and fever [see Adverse Reactions (6.2) ] . 5.5 Hypersensitivity Including Angioedema Hypersensitivity including angioedema has been reported in patients receiving prasugrel, including patients with a history of hypersensitivity reaction to other thienopyridines [see Contraindications (4.3) and Adverse Reactions (6.2) ] .
禁忌
4 CONTRAINDICATIONS Active pathological bleeding (4.1) Prior transient ischemic attack or stroke (4.2) Hypersensitivity to prasugrel or any component of the product (4.3) 4.1 Active Bleeding Prasugrel tablets are contraindicated in patients with active pathological bleeding such as peptic ulcer or intracranial hemorrhage (ICH) [see Warnings and Precautions (5.1) and Adverse Reactions (6.1) ] . 4.2 Prior Transient Ischemic Attack or Stroke Prasugrel tablets are contraindicated in patients with a history of prior transient ischemic attack (TIA) or stroke. In TRITON-TIMI 38 ( TR ial to Assess I mprovement in T herapeutic Outcomes by O ptimizing Platelet Inhibitio N with Prasugrel), patients with a history of TIA or ischemic stroke (>3 months prior to enrollment) had a higher rate of stroke on prasugrel tablets (6.5%; of which 4.2% were thrombotic stroke and 2.3% were intracranial hemorrhage [ICH]) than on clopidogrel (1.2%; all thrombotic). In patients without such a history, the incidence of stroke was 0.9% (0.2% ICH) and 1.0% (0.3% ICH) with prasugrel tablets and clopidogrel, respectively. Patients with a history of ischemic stroke within 3 months of screening and patients with a history of hemorrhagic stroke at any time were excluded from TRITON-TIMI 38. Patients who experience a stroke or TIA while on prasugrel tablets generally should have therapy discontinued [see Adverse Reactions (6.1) and Clinical Studies (14) ] . 4.3 Hypersensitivity Prasugrel tablets are contraindicated in patients with hypersensitivity (e.g., anaphylaxis) to prasugrel or any component of the product [see Adverse Reactions (6.2) ] .
薬物動態
12.3 Pharmacokinetics Prasugrel is a prodrug and is rapidly metabolized to a pharmacologically active metabolite and inactive metabolites. The active metabolite has an elimination half-life of about 7 hours (range 2 to 15 hours). Healthy subjects, patients with stable atherosclerosis, and patients undergoing PCI show similar pharmacokinetics. Absorption and Binding Following oral administration, ≥79% of the dose is absorbed. The absorption and metabolism are rapid, with peak plasma concentrations (C max ) of the active metabolite occurring approximately 30 minutes after dosing. The active metabolite’s exposure (AUC) increases slightly more than proportionally over the dose range of 5 to 60 mg. Repeated daily doses of 10 mg do not lead to accumulation of the active metabolite. In a study of healthy subjects given a single 15 mg dose, the AUC of the active metabolite was unaffected by a high-fat, high-calorie meal, but C max was decreased by 49% and T max was increased from 0.5 to 1.5 hours. Prasugrel can be administered without regard to food. The active metabolite is bound about 98% to human serum albumin. Metabolism and Elimination Prasugrel is not detected in plasma following oral administration. It is rapidly hydrolyzed in the intestine to a thiolactone, which is then converted to the active metabolite by a single step, primarily by CYP3A4 and CYP2B6 and to a lesser extent by CYP2C9 and CYP2C19. The estimates of apparent volume of distribution of prasugrel’s active metabolite ranged from 44 to 68 L and the estimates of apparent clearance ranged from 112 to 166 L/hr in healthy subjects and patients with stable atherosclerosis. The active metabolite is metabolized to two inactive compounds by S-methylation or conjugation with cysteine. The major inactive metabolites are highly bound to human plasma proteins. Approximately 68% of the prasugrel dose is excreted in the urine and 27% in the feces as inactive metabolites. Specific Populations Geriatric Patients In a study of 32 healthy subjects between the ages of 20 and 80 years, age had no significant effect on pharmacokinetics of prasugrel’s active metabolite or its inhibition of platelet aggregation. In TRITON-TIMI 38, the mean exposure (AUC) of the active metabolite was 19% higher in patients ≥75 years of age than in patients <75 years of age. In a study in subjects with stable atherosclerosis, the mean exposure (AUC) to the active metabolite of prasugrel in subjects ≥75 years old taking a 5 mg maintenance dose was approximately half that seen in subjects 45 to 64 years old taking a 10 mg maintenance dose [see Warnings and Precautions (5.1) and Use in Specific Populations (8.5) ] . Body Weight The mean exposure (AUC) to the active metabolite is approximately 30 to 40% higher in subjects with a body weight of <60 kg than in those weighing ≥60 kg. In a study in subjects with stable atherosclerosis, the AUC of the active metabolite on average was 38% lower in subjects <60 kg taking 5 mg (N=34) than in subjects ≥60 kg taking 10 mg (N=38) [see Dosage and Administration (2) , Warnings and Precautions (5.1) , Adverse Reactions (6.1) , and Use in Specific Populations (8.6) ] . Male and Female Patients Pharmacokinetics of prasugrel’s active metabolite is similar in men and women. Racial or Ethnic Groups Exposure in subjects of African and Hispanic descent is similar to that in Caucasians. In clinical pharmacology studies, after adjusting for body weight, the AUC of the active metabolite was approximately 19% higher in Chinese, Japanese, and Korean subjects than in Caucasian subjects. Smoking Pharmacokinetics of prasugrel’s active metabolite is similar in smokers and nonsmokers. Patients with Renal Impairment Pharmacokinetics of prasugrel’s active metabolite and its inhibition of platelet aggregation is similar in patients with moderate renal impairment (CrCL=30 to 50 mL/min) and healthy subjects. In patients with end-stage renal disease, exposure to the active metabolite (both C max and AUC (0-t last )) was about half that in healthy controls and patients with moderate renal impairment [see Warnings and Precautions (5.1) and Use in Specific Populations (8.7) ] . Patients with Hepatic Impairment Pharmacokinetics of prasugrel’s active metabolite and inhibition of platelet aggregation was similar in patients with mild to moderate hepatic impairment compared to healthy subjects. The pharmacokinetics and pharmacodynamics of prasugrel’s active metabolite in patients with severe hepatic disease have not been studied [see Warnings and Precautions (5.1) and Use in Specific Populations (8.8) ] . Drug Interaction Studies Potential for Other Drugs to Affect Prasugrel Inhibitors of CYP3A - Ketoconazole (400 mg daily), a selective and potent inhibitor of CYP3A4 and CYP3A5, did not affect prasugrel-mediated inhibition of platelet aggregation or the active metabolite’s AUC and T max , but decreased the C max by 34% to 46%. Therefore, CYP3A inhibitors such as verapamil, diltiazem, indinavir, ciprofloxacin, clarithromycin, and grapefruit juice are not expected to have a significant effect on the pharmacokinetics of the active metabolite of prasugrel [see Drug Interactions (7.4) ] . Inducers of Cytochromes P450 - Rifampicin (600 mg daily), a potent inducer of CYP3A and CYP2B6 and an inducer of CYP2C9, CYP2C19, and CYP2C8, did not significantly change the pharmacokinetics of prasugrel’s active metabolite or its inhibition of platelet aggregation. Therefore, known CYP3A inducers such as rifampicin, carbamazepine, and other inducers of cytochromes P450 are not expected to have significant effect on the pharmacokinetics of the active metabolite of prasugrel [see Drug Interactions (7.4) ] . Drugs that Elevate Gastric pH - Daily coadministration of ranitidine (an H 2 blocker) or lansoprazole (a proton pump inhibitor) decreased the C max of the prasugrel active metabolite by 14% and 29%, respectively, but did not change the active metabolite’s AUC and T max . In TRITON-TIMI 38, prasugrel was administered without regard to coadministration of a proton pump inhibitor or H 2 blocker [see Drug Interactions (7.4) ] . Statins - Atorvastatin (80 mg daily), a drug metabolized by CYP450 3A4, did not alter the pharmacokinetics of prasugrel’s active metabolite or its inhibition of platelet aggregation [see Drug Interactions (7.4) ] . Heparin - A single intravenous dose of unfractionated heparin (100 units/kg) did not significantly alter coagulation or the prasugrel-mediated inhibition of platelet aggregation; however, bleeding time was increased compared with either drug alone [see Drug Interactions (7.4) ] . Aspirin - Aspirin 150 mg daily did not alter prasugrel-mediated inhibition of platelet aggregation; however, bleeding time was increased compared with either drug alone [see Drug Interactions (7.4) ] . Warfarin - A significant prolongation of the bleeding time was observed when prasugrel was coadministered with 15 mg of warfarin [see Drug Interactions (7.1) ] . Potential for Prasugrel to Affect Other Drugs In vitro metabolism studies demonstrate that prasugrel’s main circulating metabolites are not likely to cause clinically significant inhibition of CYP1A2, CYP2C9, CYP2C19, CYP2D6, or CYP3A, or induction of CYP1A2 or CYP3A. Drugs Metabolized by CYP2B6 - Prasugrel is a weak inhibitor of CYP2B6. In healthy subjects, prasugrel decreased exposure to hydroxybupropion, a CYP2B6-mediated metabolite of bupropion, by 23%, an amount not considered clinically significant. Prasugrel is not anticipated to have significant effect on the pharmacokinetics of drugs that are primarily metabolized by CYP2B6, such as halothane, cyclophosphamide, propofol, and nevirapine. Effect on Digoxin - The potential role of prasugrel as a Pgp substrate was not evaluated. Prasugrel is not an inhibitor of Pgp, as digoxin clearance was not affected by prasugrel coadministration [see Drug Interactions (7.4) ] . Morphine - Coadministration of 5 mg intravenous morphine with 60 mg loading dose of prasugrel in healthy adults decreased the C max of prasugrel’s active metabolite by 31% with no change in AUC, T max , or inhibition of ADP-induced platelet aggregation. ADP-induced platelet aggregation was higher up to 2 hours following 60 mg loading dose of prasugrel in stable patients more than 1 year after an ACS who were coadministered morphine. In the patients with a 2-hour delay in the onset of platelet aggregation (5 of 11), T max was delayed and prasugrel active metabolite levels were significantly lower at 30 min (5 vs 120 ng/mL) following coadministration with morphine.