A 58-year-old man with hypertension and diabetes presents to the emergency department 2.5 hours after onset of acute left-sided weakness and slurred speech. On examination, he has a National Institutes of Health Stroke Scale (NIHSS) score of 8. CT head (non-contrast) shows no hyperdensity or hypodensity. Blood glucose is 180 mg/dL. What is the most appropriate immediate next step in management?