Conditions: Blood Platelets Clopidogrel
Keywords: blood platelets platelet aggregation inhibitors antiplatelet drugs clopidogrel
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 15
Healthy volunteers: yes

Brief summary:
Clopidogrel is a medication that is used to decrease the ability of platelets to form blood clots.

The theory has been proposed that, in patients with coronary artery disease or stroke, increased platelet function after discontinuation of clopidogrel therapy is associated with an increased clotting risk. However, this theory has never been rigorously tested.

The goal of this research is to determine whether discontinuation of clopidogrel results in increased platelet function.

Detailed description:
In this study, we will address the question: does discontinuation of clopidogrel result in platelet hyperreactivity? We will perform a double-blind, placebo-controlled, crossover study in normal subjects, in whom platelet reactivity will be measured before clopidogrel or placebo, during clopidogrel or placebo, and at various time points after discontinuation of clopidogrel or placebo. The dose of clopidogrel will be the standard, FDA-approved dose: 75 mg daily. All subjects will be treated with aspirin 81 mg daily throughout the 57 days of study assessment in both the clopidogrel arm and the placebo arm, because the clinically relevant question is: in patients who remain on aspirin, does discontinuation of clopidogrel result in platelet hyperreactivity?

Arms:
arm 1: The subjects will be randomized to clopidogrel 75 mg plus aspirin 81 mg orally daily for 14 days. The study drug (i.e., clopidogrel) will then be discontinued and aspirin continued for another 43 days. arm 2: The subjects will be randomized to placebo plus aspirin 81 mg orally daily for 14 days. The study drug (i.e., placebo) will then be discontinued and aspirin continued for another 43 days.

Interventions: intervention 1: clopidogrel + aspirin intervention 2: placebo intervention 3: Aspirin
Intervention descriptions: intervention 1: Clopidogrel 75mg plus aspirin 81mg, tablet by mouth daily for 14 days. intervention 2: Placebo plus aspirin 81 mg, tablet by mouth daily for 14 days. intervention 3: Aspirin 81mg tablet by mouth continued daily alone for 43 days after day 14.

Protocol document: