Formulas for converting doses for children

Paediatric doses

This chapter contains basic formulae for calculating doses for children. It is important to check for additional information in specialist literature, especially for strong medicines, as doses may differ from those calculated. The same rule applies to doses in geriatric patients and in patients with renal and liver diseases, whose level of absorption, metabolism and excretion of the drug may differ significantly from the established standards.

For children over 1 year of age, the following formulas apply:

Gowling’s rule.

Dc– dose for child.

Young’s rule.

Dc – dose for child (for children 2 – 12 years of age).

Clark’s rule based on the child’s body weight. (do not use the formula in obese children).

Dc– dose for child (above 2 years of age).

Rule based on the child’s body surface area.

Dd– dawka dla dziecka

^ – 1.8 is the average body surface area of an adult with the weight of 70 kg and height of 170 cm.

Table of normal doses for children

Age (above) Body weight [kg] [kg] Body surface area [m2] Percentage of adult dose
4 weeks 3,5 0,21 12,5*
2 months 4,5 0,28 15,0*
4 months 6,5 0,36 20,0*
1 year 10 0,49 25,0
3 years 15 0,65 33,0
7 years 23 0,87 50,0
12 years 40 1,27 75,0
Adult 65 1,76 100,0

*- not applicable for premature infants due to hepatic and renal impairment.