Initial Drug Treatment for Acute Ischaemic Stroke
Time-Based Treatment Algorithm
- The American Heart Association recommends IV r-tPA as the definitive first-line treatment for patients presenting within 3 hours of symptom onset, with a dose of 0.9 mg/kg (maximum 90 mg), which significantly improves functional outcomes, with a number needed to treat of approximately 8 for achieving minimal or no disability (Grade 1A evidence) 1, 4
- The American College of Chest Physicians strongly recommends IV r-tPA for patients within 3 hours of symptom onset, as it produces a 12% absolute increase in patients achieving minimal or no disability (modified Rankin Scale 0-1: 39% vs 26% placebo) 4
- For patients between 3 to 4.5 hours of symptom onset, IV r-tPA should be considered using ECASS III criteria (Grade 2C evidence) 1, 2, 4
Critical Dosing Specifications
- The standard dose of IV r-tPA is 0.9 mg/kg with a maximum of 90 mg total, with 10% administered as IV bolus over 1 minute and the remaining 90% infused over 60 minutes, based on the landmark NINDS trial 1, 5, 4
Aspirin as Alternative/Adjunctive Therapy
- The American Heart Association recommends aspirin 160-325 mg to be initiated within 48 hours for patients who cannot receive r-tPA or after the thrombolytic window has closed (Grade 1A evidence) 1, 2, 6
- Aspirin must NOT be given within 24 hours of r-tPA administration due to increased bleeding risk 5, 7, 6
Important Safety Considerations
- Systolic BP must be ≤185 mm Hg and diastolic ≤105 mm Hg before r-tPA treatment, and blood pressure requiring continuous sodium nitroprusside infusion may be too unstable for r-tPA administration 5
- Neurological assessments should be performed every 15 minutes during infusion, then every 30 minutes for 6 hours, then hourly until 24 hours, and blood pressure monitoring every 15 minutes for 2 hours, then every 30 minutes for 6 hours, then hourly 5
Anticoagulation Is NOT Recommended Acutely
- The American College of Chest Physicians recommends against urgent anticoagulation with heparin, low-molecular-weight heparin, or heparinoids, as it does NOT improve outcomes and increases bleeding risk (Grade 1A evidence against) 1, 2, 7