Inclusion Criteria- Patients who have suffered an acute ischemic stroke and can be evaluated and treatment initiated within 6 hours after the onset of symptoms (Onset is defined as the time that which the patient was last seen in a normal state, or bedtime for unwitnessed strokes occurring during the night).
- Patients who have a three dimensionally measurable lesion compatible with an acute ischemic stroke measured using MRI.
- Patients who have a National Institutes of Health Stroke Scale (NIHSS) score of at least 7 but not more than 23 and who are conscious.
- Patients who are able to provide written informed consent or have consent provided by a legally authorized representative.
- Patients who are at least 18 years of age.
- Other criteria as specified in the study protocol
Exclusion Criteria- Patients who have received alteplase (t-PA) for the current stroke episode. It is assumed that all patients who are eligible will receive treatment with t-PA.
- Patients who have disability and functional limitations prior to the current stroke episode (e.g. deficit resulting from a prior stroke).
- Patients who have brain hemorrhage.
- Patients who have stroke of the brainstem or cerebellum.
- Patients who cannot be evaluated using MRI due to the presence of a pacemaker, claustrophobia, need for sedation, etc.
- Patients who have renal (kidney) disease or insufficiency.
- Patients who have active epilepsy or convulsions during the current stroke episode.
- Patients who are IV drug users or are inebriated.
- Patients who have a history of drug-related anaphylaxis.
- Patients who have taken sedatives, anticonvulsants, or any medication with sedating effects in the 10 days prior study enrollment.
- Patients who have taken more than 1.3 g of aspirin per day in the 2 days prior to enrollment.
- Patients who have a known vitamin hypersensitivity.
- Other exclusion criteria as specified by the study protocol.