The drug dosage will be – 5 mcg prescribed for 1 kilogram body weight Therefore, as the body weight is 18 kilograms, the child can receive maximum of 5 mcg x 18 kilograms = 90 mcg of the prescribed drug.

3d) Drug dosage as per body surface area:

Patient 1 weighs 75kg and is 1.6 metres tall. The drug dosage prescribed is 10mg/day.

As per the Mosteller formula, Body Surface Area (BSA) m2 (Mosteller, 1987) = √ height (cm) x weight (kg) / 3600 Weight: 75kg; Height: 1.6 metres or 160cms √ 75kg x 160cms / 3600 = √ 12000/ 3600 = √120/ 36 = 1.825 m2 If the dosage of drug is 10mg/ m2/day, then the dosage will be 1.825 m2 x 10 mg = 18.25 mg /day