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 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.

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.