A medication is dosed at 3 mg/kg. The patient weighs 4 kg. What is the dose?

A medication is dosed at 3 mg/kg. The patient weighs 4 kg. What is the dose?

• A. 12 mg
• B. 6 mg
• C. 9 mg
• D. 8 mg

Answer: (A)

Dosing per kilogram means you scale the amount of medication by the patient’s weight. Multiply the dose per kg by the weight in kilograms to get the total dose in milligrams. So, 3 mg/kg × 4 kg = 12 mg, giving a total dose of 12 mg. The other numbers would come from different weights (for example, 3 mg/kg × 2 kg = 6 mg, or 3 mg/kg × 3 kg = 9 mg), but with a 4 kg patient the correct total is 12 mg.

Dosing per kilogram means you scale the amount of medication by the patient’s weight. Multiply the dose per kg by the weight in kilograms to get the total dose in milligrams. So, 3 mg/kg × 4 kg = 12 mg, giving a total dose of 12 mg. The other numbers would come from different weights (for example, 3 mg/kg × 2 kg = 6 mg, or 3 mg/kg × 3 kg = 9 mg), but with a 4 kg patient the correct total is 12 mg.