Clopidogrel/Aspirin Interaction Study (INTERACTION)

Population Health Research Institute (PHRI)

Status and phase: Completed; Phase 4

Conditions: Coronary Artery Disease

Treatments: Drug: Clopidogrel; Drug: Aspirin

Study type: Interventional

Funder types: Other

Identifiers

NCT01102439

10-082

Details and patient eligibility

About

This study will explore the effect of different doses of aspirin on the effects of double-dose or standard dose clopidogrel.

Full description

Study Hypothesis: Patients receiving double-dose compared with standard-dose clopidogrel will have increased blood concentrations of the active metabolite of clopidogrel and greater inhibition of ADP-induced platelet aggregation when also treated with acetylsalicylic acid (ASA) 325 mg/d as compared to ASA 81 mg/d.

Enrollment: 82 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• > 1 month post myocardial infarction (MI), unstable angina or stent patients with stable condition
• Receiving regular ASA (81mg/d) and clopidogrel (75mg/d) for at least 1 week
• Written informed consent

Exclusion criteria

• Age < 18 years old
• Liver disease with transaminases and/or bilirubin > 1.5x upper limits of normal (ULN) (within 3 months of randomization)
• Renal impairment with creatinine clearance < 30 ml/min (within 3 months of randomization)
• Platelet count < 100x109/L and/or Hb< 100g/L (within 3 months of randomization)
• Use of oral anticoagulants or nonsteroidal antiinflammatory drug (NSAID) within the last 10 days or planned use during the study
• Use of antiplatelet agent other than aspirin and clopidogrel within the last 10 days
• High risk of bleeding (e.g. recent gastrointestinal bleeding, bleeding diathesis)
• Uncontrolled hypertension (> 180/110mmHg)
• Current smoker with ≥ 5 cigarettes/day
• Previously entered in this study or just finished other study within 2 weeks before recruitment
• Medical, geographic, or social factors making study participation impractical, or inability to provide written informed consent

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Factorial Assignment

Masking: None (Open label)

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82 participants in 4 patient groups

Standard dose clopidogrel

Active Comparator group

Description:

300 mg Loading x 1 day, 75 mg/d x 13 days

Treatment:

Drug: Clopidogrel

Drug: Clopidogrel

Double dose clopidogrel

Experimental group

Description:

600 mg Loading x 1 day, 150 mg/d x 6 days, 75 mg/d x 7 days

Treatment:

Drug: Clopidogrel

Drug: Clopidogrel

Standard dose aspirin

Active Comparator group

Description:

Aspirin 81mg/d x 14 days

Treatment:

Drug: Aspirin

Drug: Aspirin

High dose aspirin

Experimental group

Description:

Aspirin 325 mg/d x 14 days

Treatment:

Drug: Aspirin

Drug: Aspirin