Calculation of Doses for Children
Young’s Rule = expression used to determine a drug dosage for children. The correct dosage is calculated by dividing the child’s age by an amount equal to the child’s age plus 12 and then multiplying by the usual adult dose.
Formula:
Adult Dose * (Age ÷ (Age+12)) = Child’s Dose
Example:
If the drug dose for an adult is 750 mg, how much should a 10 year old child receive?
Adult Dose * (Age ÷ (Age+12)) = Child’s Dose
750 mg * (10 ÷ (10+12)) = Child’s Dose
750 mg * (10 ÷ 22) = Child’s Dose
750 mg * 0.4545 = Child’s Dose
340.91 mg = Child’s Dose
Clark’s Rule = expression used to determine a drug dosage for children. The procedure is to take the child’s weight in pounds, divide by 150 lb, and multiply the fractional result by the adult dose to find the equivalent child dosage.
Formula:
Adult Dose * (Child’s Weight in pounds ÷ 150) = Childs Dose
Note: Child’s weight must be in lbs and not kg
Example:
If the drug dose for an adult is 750 mg, how much should a 50 lb child receive?
Adult Dose * (Child’s Weight in pounds ÷ 150) = Childs Dose
750 mg * (50 ÷ 150) = Child’s Dose
750 mg * (0.33333) = Child’s Dose
250 mg = Child’s Dose