A stroke patient weighing 257 pounds is prescribed alteplase at 0.9 mg/kg. What is the calculated dose in milligrams (before applying any maximum)?

• A. 90 mg
• B. 105 mg
• C. 110 mg
• D. 120 mg

Answer: (B)

The dose is based on body weight in kilograms, using a mg per kilogram order, so you first convert pounds to kilograms and then multiply by 0.9 mg/kg.

Convert weight: 257 pounds ÷ 2.2046 ≈ 116.6 kg.

Dose: 116.6 kg × 0.9 mg/kg ≈ 104.94 mg, which rounds to 105 mg.

In this context, the calculated dose before any maximum is about 105 mg. In practice, however, alteplase for stroke is capped at a maximum dose (90 mg). So while the computed value is 105 mg, the actual administered dose would be limited to 90 mg due to the maximum.