What is the standard alteplase dose for acute ischemic stroke within 4.5 hours, and how is it administered?

• A. 1.0 mg/kg total; maximum 90 mg; 10% as bolus, remainder over 60 minutes.
• B. 0.9 mg/kg total; maximum 90 mg; 10% as bolus, remainder over 60 minutes.
• C. 0.9 mg/kg total; maximum 80 mg; 10% as bolus, remainder over 60 minutes.
• D. 0.9 mg/kg total; maximum 90 mg; 50% as bolus, remainder over 60 minutes.

Answer: (B)

Dosing for IV alteplase in acute ischemic stroke within 4.5 hours uses 0.9 mg/kg total, with a maximum of 90 mg. Ten percent of the total dose is given as an IV bolus, and the remaining 90% is infused over 60 minutes. This approach provides rapid onset of clot-dissolving action through the bolus, then maintains the effect with the slower infusion to balance effectiveness with bleeding risk. The 0.9 mg/kg figure and the 90 mg ceiling reflect aligning efficacy with safety across different body weights. Deviations such as a higher per‑kg dose, a different maximum, or a larger proportion given as a bolus would increase the risk of hemorrhage or under-satisfy the infusion profile.