A neonate weighs 8.5 kg and is prescribed amoxicillin 90 mg/kg/day in three divided doses. The suspension concentration is 250 mg/mL. How many milliliters are needed per dose?

• A. 0.8 mL
• B. 1.0 mL
• C. 1.2 mL
• D. 1.5 mL

Answer: (B)

Dosing a drug by weight and converting the required milligrams to milliliters using the suspension’s concentration.

Calculate the total daily amount: 8.5 kg × 90 mg/kg/day = 765 mg per day. Since the dose is divided into three administrations, each dose is 765 mg ÷ 3 = 255 mg per dose. With a suspension concentration of 250 mg/mL, the volume needed per dose is 255 mg ÷ (250 mg/mL) = 1.02 mL. In practice, this is rounded to about 1.0 mL per dose.