Weight-based dosing for acetaminophen and ibuprofen aims to balance efficacy with safety by adjusting dose to what?

• A. Temperature
• B. Age
• C. Weight
• D. Hair color

Answer: (C)

Weight-based dosing is used because how much drug reaches the body and how it’s cleared depend on body size. Using weight lets us deliver a similar level of medication exposure across children of different sizes, which helps achieve effective fever or pain relief while keeping safety margins. In practice, doses for acetaminophen and ibuprofen are given in milligrams per kilogram of body weight, so the dose scales with how much the child weighs. For example, acetaminophen is commonly given around 10–15 mg per kilogram per dose every 4–6 hours, and ibuprofen about 5–10 mg per kilogram per dose every 6–8 hours, with daily maximums. Weight-based dosing ensures larger children get more medication and smaller children get less, reducing the risk of underdosing or overdose. Age alone isn’t precise because children of the same age can vary a lot in size, and temperature doesn’t determine how much medicine is needed.