Worked example

Weight-based dose (mg/kg) — practice problem 3

A patient weighs 55 lb. The prescriber orders acetaminophen 20 mg/kg/dose.

Weight55 lb
Ordered20 mg/kg/dose

How many mg is the dose?

Answer: 500 mg

Step-by-step solution

1. Convert the patient's weight to kilograms
55 lb × ( 1 kg ÷ 2.2 lb )
= 25 kg
2. Multiply weight by the ordered mg/kg
25 kg × ( 20 mg ÷ 1 kg )
= 500 mg

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