The order reads 20 mg/kg of acetaminophen for a child who weighs 29 lb. How many milligrams should be administered (round to nearest whole number)?

The order reads 20 mg/kg of acetaminophen for a child who weighs 29 lb. How many milligrams should be administered (round to nearest whole number)?

• A. 260 mg
• B. 264 mg
• C. 248 mg
• D. 270 mg

Answer: (B)

Weight-based dosing for acetaminophen is calculated by converting the child’s weight to kilograms and then multiplying by the dose per kilogram. Use the common conversion: 29 lb ÷ 2.2 lb/kg ≈ 13.18 kg. Multiply by 20 mg/kg: 13.18 × 20 ≈ 263.6 mg. Rounding to the nearest whole milligram gives 264 mg. In practice, using 2.2 lb per kg is a standard approximation, which is why this rounds to 264 mg rather than a slightly lower value that might come from a more exact pound-to-kilogram conversion. This illustrates how weight-based dosing and rounding determine the administered milligram amount.

Weight-based dosing for acetaminophen is calculated by converting the child’s weight to kilograms and then multiplying by the dose per kilogram. Use the common conversion: 29 lb ÷ 2.2 lb/kg ≈ 13.18 kg. Multiply by 20 mg/kg: 13.18 × 20 ≈ 263.6 mg. Rounding to the nearest whole milligram gives 264 mg. In practice, using 2.2 lb per kg is a standard approximation, which is why this rounds to 264 mg rather than a slightly lower value that might come from a more exact pound-to-kilogram conversion. This illustrates how weight-based dosing and rounding determine the administered milligram amount.