If a 12 kg child is treated with paracetamol suspension at 15 mg/kg per dose every 6 hours with a maximum of four doses per day, what is the maximum total volume per day in milliliters for this child given a suspension of 250 mg/5 mL?

• A. 14.4 mL
• B. 12 mL
• C. 18 mL
• D. 24 mL

Answer: (A)

The key idea is converting a weight-based daily dose into a total daily volume using the suspension’s concentration.

First, find the amount of drug per dose: 12 kg × 15 mg/kg = 180 mg per dose.

You can give up to four doses in a day, so the maximum daily dose is 180 mg/dose × 4 doses = 720 mg/day.

Convert this to volume using the suspension concentration. The suspension is 250 mg in 5 mL, which is 50 mg/mL. So the volume needed for 720 mg is 720 mg ÷ 50 mg/mL = 14.4 mL per day.

For intuition, that’s 180 mg per dose ÷ 50 mg/mL = 3.6 mL per dose, and 3.6 mL × 4 doses = 14.4 mL total.

Answer: maximum total volume per day is 14.4 mL.