PHCP prescribes ondansetron 0.15 mg/kg IV to a pediatric client who weighs 40 lb. The medication label reads 2 mg/mL. How many milliliters will the nurse administer? Round to the nearest tenth.

• A. 0.9 mL
• B. 1.0 mL
• C. 1.4 mL
• D. 2.0 mL

Answer: (C)

Calculating pediatric doses uses mg/kg, then convert weight to kilograms and compute the total milligrams, followed by converting to milliliters using the medication’s concentration. A weight of 40 lb is about 18.14 kg. The ordered dose is 0.15 mg/kg, so the total dose is 18.14 × 0.15 ≈ 2.72 mg. The solution is 2 mg/mL, so the required volume is 2.72 ÷ 2 = 1.36 mL, which rounds to 1.4 mL. Therefore, administer 1.4 mL.