The determination of a drug dose for children is rather difficult. Some drugs need to be adjusted due to severe adverse effects, whereas with other drugs a special children's dose can be used. When there is no indication for dose, the dose can be calculated as a percentage of the normal adult dose. In this case the schaal van Denekamp can be very useful. This scale corrects for abnormal weight or height in children. In normal children one can read the dosage by connecting a line in column A (years of age) and B (weight in kilos) with column C, which then shows the percentage of the adult dose.
When weight or height is abnormal, one also should read from column D (height in cm) towards column C (body surface in square meters). The mean of both points in column C is the percentage of the dose.
In order to calculate the body surface, the formula of Haycock can be used:
Body surface (in m2 = (weight in kg)0,5378 x (height in cm)0,3964 x 0,024265
What is a substantial limitation of using the scale of Denekamp?
Extra info: Children generally have a higher metabolism and thus require larger dosages. A child’s organs (GI-tract, kidneys, liver etc.) are each in different stages of maturation and it is thus impossible to correct the dose of all drugs with one scale, because the pharmacokinetics (absorption, distribution, metabolism, excretion) differ per drug.