The purpose of this study is to determine whether simvastatin treatment started within the first 12 hours from stroke onset improves neurological and functional outcomes, evaluated at seventh day/discharge or at the third month.

Also, to demonstrate that simvastatin is safe and not associated with higher rates of hemorrhagic transformation in patients who receive thrombolysis.

Inclusion Criteria:

• Patients older than 18 years acute ischemic stroke (less than 12 hours from stroke onset).
• Stroke involving MCA-ACA-PCA.
• NIHSS score 4 to 22.
• Previous modified Rankin Scale score of 1 or 0.
• Patient or proxy informed consent.
• Patients not taking statins for the past six months.

Exclusion Criteria:

• Pregnancy or breastfeeding.
• Clinical or radiological evidence on admission of intracranial hemorrhage, hemorrhagic infarction or tumor.
• Seizures at the time of inclusion.
• Complete or substantial recovery prior to randomization.
• Patients with ipsilateral neurological deficit that may mask the evaluation of the current event.
• Liver disease (AST or ALT more than twice upper normality limit).
• Cardiogenic shock or relevant cardiac failure.
• Patients with more than five times upper normality limit of CPK.
• Myocardial infarction or any other thromboembolic event within the previous 30 days.
• Active infection by the time of inclusion.
• Documented hypersensibility to statins.
• Drug abuse.
• Expected short life-expectancy related to other systemic diseases.