Worked example

Weight-based dose (mg/kg) — practice problem 14

A patient weighs 176 lb. The prescriber orders vancomycin 15 mg/kg/day divided into 4 equal doses.

Weight176 lb
Ordered15 mg/kg/day
Frequency4 doses/day

How many mg is each dose?

Answer: 300 mg per dose

Step-by-step solution

1. Convert the patient's weight to kilograms
176 lb × ( 1 kg ÷ 2.2 lb )
= 80 kg
2. Multiply weight by the ordered mg/kg/day
80 kg × ( 15 mg ÷ 1 kg )
= 1200 mg/day
3. Divide the daily dose into 4 equal doses
1200 mg/day ÷ 4 doses
= 300 mg per dose

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