Inclusion Criteria1. 20 years old or above.
2. History of TIA or completed ischemic stroke
3. Signed informed consent.
4. Patient with score < 2 on modified Rankin's Classification of Neurological Status.
Exclusion Criteria1. Patients with known or suspected prior intracranial haemorrhage or history of brain injury or brain tumor.
2. Disorders related to syncope, drop attacks, congenital vascular malformation, aneurysm, angioma, or epilepsy, psychiatric disorders.
3. Peptic ulcer or gastrointestinal bleeding within 6 months.
4. History of hypersensitivity or intolerance to study drugs or aspirin.
5. Experienced habitual headache (any form) within the past 3 months.
6. History of dysphasia, dysphagia, dementia, or unconsciousness.
7. Patients currently taking other medications known to cause headaches (e.g., nitrates).
8. Patients with deteriorating angina, subvalvular aortic stenosis or hemodynamic liability (e.g., in conjunction with a recent myocardial infarction).
9. Uncontrolled hypertension (SBP > 220 mmHg, DBP> 120 mmHg) or life-threatening disease.
10. Any significant disorders, such as chronic renal failure (serum creatinine > 2.0 mg/dl), neoplasia.
11. SGPT, SGOT value greater than 2 times of the upper normal limit.
12. Insulin dependent diabetes mellitus or poorly controlled non-insulin dependent diabetes mellitus (AC sugar > 300 mg/dl).
13. Use of other anticoagulants, such as anti-coagulated agents or NSAIDsS.
14. History of alcohol and/or drug abuse.
15. Having participated in other investigational drug study within 3 months prior to study entry.
16. Pregnant or lactating women or women of childbearing potential whom are not practicing reliable birth control.
17. The patients who take methylxanthine-containing drinks or foods (coffee, black tea, cola, energy drink, etc.) more than 4 cups of coffee or it's equivalents.