Which adenosine diphosphate receptor antagonist does not work any better than aspirin but is recommended for those patients allergic to aspirin?

Clopidogrel (Plavix)

Clopidogrel (Plavix) is indicated in thrombosis and coronary artery disease - side effects include a low risk of TTP (thrombotic thrombocytopenia purpura), bleeding, hypersensitivity, abdominal pain, constipation - resistance to clopidogrel (Plavix) can be seen if the patient has a defect in CYP450 enzymes - prodrug doesnt get converted to active form.