A dose calls for 0.8 mg/kg; the patient weighs 12.5 kg. What is the total dose?

A dose calls for 0.8 mg/kg; the patient weighs 12.5 kg. What is the total dose?

• A. 1 mg
• B. 100 mg
• C. 10 mg
• D. 8 mg

Answer: (C)

Multiply the dose per kilogram by the patient’s weight in kilograms to get the total dose. Here, 0.8 mg/kg × 12.5 kg equals 0.8 × 12.5 mg. Break it down: 0.8 × 12 = 9.6 and 0.8 × 0.5 = 0.4, so 9.6 + 0.4 = 10 mg. The total dose is 10 mg. The other options don’t fit the given numbers: 1 mg would require a much smaller total (or a much smaller weight), 100 mg would require a much larger dose per kg or weight, and 8 mg would come from a weight of 10 kg at 0.8 mg/kg, not 12.5 kg.

Multiply the dose per kilogram by the patient’s weight in kilograms to get the total dose. Here, 0.8 mg/kg × 12.5 kg equals 0.8 × 12.5 mg. Break it down: 0.8 × 12 = 9.6 and 0.8 × 0.5 = 0.4, so 9.6 + 0.4 = 10 mg. The total dose is 10 mg. The other options don’t fit the given numbers: 1 mg would require a much smaller total (or a much smaller weight), 100 mg would require a much larger dose per kg or weight, and 8 mg would come from a weight of 10 kg at 0.8 mg/kg, not 12.5 kg.