A pediatric patient weighs 18 kg. How should you approach a weight-based dose on the MAR?

• A. Calculate dose based on age.
• B. Double the adult dose.
• C. Calculate dose using mg/kg as per order, convert to volume if needed, and verify pediatric dosing guidelines.
• D. Use a fixed pediatric dose regardless of weight.

Answer: (C)

In pediatric dosing, the amount given is based on the child’s weight because drug exposure and effects scale with body size and maturation. Start with the order written as milligrams per kilogram per dose. Multiply by the child’s weight (18 kg) to get the total milligrams needed per dose. Then convert to a volume if the medication is a liquid using its concentration (for example, mg/mL). After calculating, verify the dose against pediatric dosing guidelines to ensure it falls within the recommended mg/kg range and respects any maximum per-dose or per-day limits, as well as any age- or condition-specific adjustments. Always confirm the route and the medication’s concentration and double-check the math before administration.

For example, if the order is 10 mg/kg per dose, the dose would be 10 × 18 = 180 mg per dose. If the liquid form is 50 mg/mL, that would be 180 ÷ 50 = 3.6 mL to administer.

Rationale for the other approaches: relying on age alone ignores weight differences; using a fixed multiplier of an adult dose doesn’t account for the child’s size or developmental pharmacokinetics; and fixed pediatric doses that don’t consider weight can lead to under- or overdosing. Weight-based dosing with verification is the safe, standard method.