Clopidogrel and Aspirin Interaction Study-2

Phase 4

Completed

• Conditions: Drug Action Increased
• Interventions: Drug: Clopidogrel; Drug: Aspirin

• Registration Number: NCT01341964
• Lead Sponsor: Population Health Research Institute

Brief Summary

Clopidogrel and aspirin are commonly used in combination to prevent heart attacks and to prevent blockage of stents. Both clopidogrel and aspirin work by preventing platelets (sticky cells that circulate in the blood) from forming blood clots in the arteries supplying oxygen to the heart and in stents. The investigators hypothesize that aspirin 325mg compared with aspirin 81 mg will increase blood levels of the active metabolite of clopidogrel in patients with a history of coronary artery disease who receive a 600mg loading dose of clopidogrel.

Detailed Description

Eligible patients will be randomized to receive clopidogrel 600mg + aspirin 325mg (Group A) or clopidogrel 600mg + aspirin 81mg (Group B). Patients will be fasted for at least 8 hours prior to study drug administration. Blood samples will be collected at 1 hour after study drug administration for measurement of clopidogrel active metabolite levels and genotyping.

Study Timeline

• Study First Submitted: 2011-04-25
• Study First Submitted QC: 2011-04-25
• Study First Posted: 2011-04-26
• Study Start: 2011-05
• Primary Completion: 2013-04
• Study Completion: 2013-04
• Status Verified: 2022-09
• Results First Submitted: 2022-09-12
• Results First Submitted QC: 2022-09-12
• Last Update Submitted: 2022-09-12
• Results First Posted: 2023-07-27
• Last Update Posted: 2023-07-27

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 302

Inclusion Criteria

• Stable patients >1 month post ACS (including ST elevated myocardial infarction, non-ST elevated myocardial infarction or unstable angina) or stent
• Receiving regular ASA (81mg/d) and clopidogrel (75mg/d) for at least 1 week
• Written informed consent

Exclusion Criteria

• Age < 18 years

• Liver disease with ALT or bilirubin >2x upper limits of normal (ULN)*

• Renal impairment with creatinine clearance <30 ml/min*

• Deemed to be at high risk of bleeding (e.g., recent bleeding, platelet count<100x109/L or hemoglobin <100g/L)*

• Anticoagulant or NSAID therapy within the last 5 days

• Antiplatelet agent other than aspirin and clopidogrel within the last 10 days

• Uncontrolled hypertension (>=180/110mmHg)

  • within 3 months of planned randomization

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Low dose aspirin group	Clopidogrel	Clopidogrel 600mg plus aspirin 81mg
Low dose aspirin group	Aspirin	Clopidogrel 600mg plus aspirin 81mg
Higher dose aspirin group	Aspirin	Clopidogrel 600 mg plus aspirin 325mg
Higher dose aspirin group	Clopidogrel	Clopidogrel 600 mg plus aspirin 325mg

Primary Outcome Measures

Name	Time	Method
Blood Concentration of the Active Metabolite of Clopidogrel	1 hour after loading dose of study medications	Clopidogrel active metabolite concentration will be measured by liquid chromatography tandem mass spectrometry (LC/MS) methods.

Trial Locations

Locations (1)

Population Health Research Institute, Hamilton General Hospital; 🇨🇦 Hamilton, Ontario, Canada