tPA Calculator – Stroke Dosing

Standard acute ischemic stroke protocol dictates a total Alteplase (tPA) dose of 0.9 mg per kilogram of actual body weight, up to a maximum total dose of 90 mg. Once the total target dose is established, it is divided into two distinct administration phases: an initial intravenous bolus administered over one minute, followed by the remaining medication delivered via a continuous intravenous infusion over 60 minutes. The underlying equations are: Total Dose = 0.9 mg × Weight (kg), Initial Bolus (10%) = Total Dose × 0.10, and Infusion (90%) = Total Dose × 0.90.

Consider an acute ischemic stroke patient presenting within the therapeutic window who weighs 80 kg. First, calculate the maximum allowable total dose: 0.9 mg/kg × 80 kg = 72 mg. Because 72 mg is below the absolute maximum threshold of 90 mg, proceed with this calculated total. Next, determine the initial 10% bolus dose: 72 mg × 0.10 = 7.2 mg, which is administered rapidly IV over one minute. Finally, calculate the remaining 90% infusion dose: 72 mg × 0.90 = 64.8 mg, which is infused steadily over the next 60 minutes using an infusion pump.

Always verify the patient's actual dry weight in kilograms prior to calculation, and double-check that the total calculated dose does not exceed the maximum cap of 90 mg regardless of patient weight exceeding 100 kg. Ensure the initial 10% is given strictly as an IV bolus over exactly one minute before initiating the 60-minute infusion pump for the remaining 90%. Always adhere strictly to institutional protocols and verify contraindications alongside the weight-based dosing.