This study demonstrates the effect of generic clopidogrel bisulfate (Plavitor®) in comparison with the original clopidogrel bisulfate (Plavix®) in patients with acute coronary syndrome.

Inclusion Criteria:

1. Patients with unstable angina or non-ST elevation myocardial infarction
2. Patients who are planned coronary angiography
3. Age >18 years, <75 years
4. Patients who agree to the study protocol

Exclusion Criteria:

1. Recent treatment with clopidogrel or pletaal or glycoprotein IIb/IIIa Rc antagonist
2. Active bleeding (peptic ulcer, trauma or intra-cranial hemorrhage)
3. Allergy to antiplatelet agent
4. Bleeding diasthesis (blood coagulation disorders, uncontrolled severe hypertension, history of severe bleeding)
5. History of drug abuse or alcohol abuse
6. ST elevation myocardial infarction
7. Pregnancy
8. Low platelet count (< 100,000 /L) or abnormal results of PT or PTT
9. Liver disease ( bilirubin > 2 mg/dL, AST or ALT > 100 IU)
10. Renal failure ( Cr > 2.0 mg/dL)
11. Malignancy
12. Proton pump inhibitor, NSAIDs statin (except atorvastatin)