Which unit is commonly used to calculate pediatric acetaminophen doses?

• A. mg per lb
• B. g/kg
• C. mg per cm
• D. mg/kg

Answer: (D)

Pediatric acetaminophen dosing is based on weight expressed as milligrams per kilogram per dose. Using mg/kg lets the dose scale with the child’s size, which varies a lot in pediatrics, so lighter and heavier children receive appropriate amounts rather than a one-size-fits-all number. In practice, a typical dose is about 10–15 mg/kg every 4–6 hours as needed, with a daily maximum that prevents overdosing.

Using grams per kilogram would yield doses that are too large for a child, since a single gram is 1000 mg and could easily exceed safe per-dose amounts. Dosing in mg per centimeter doesn’t relate to how much drug distributes in the body and isn’t a standard method for acetaminophen. mg per pound is less common and can introduce confusion, especially where dosing charts and labels use kilograms. Because acetaminophen dosing relies on precise weight-based calculations, mg/kg is the standard, widely accepted unit.