Estimation of dose for children

Question

Explain how dose for the children is being estimated based upon the preclinical data?

Answer 1

There exists number of ways of estimating children's doses from the preclinical (adult) data. It often depends upon the therapeutic index of drug in question (wider the therapeutic window the less accurate the child's dose required to be). Sometimes the straight weight-basis that is, 7kg child gets 1/10 dose of 70kg adult.
More accurate (so they say) is the dose based upon the body surface area (child's surface area is larger in proportion to its body weight as compared to an adult). There exist norm grams to determine the surface area from weight and height of the child.

All of these may be wrong if the clearance of drug in the child is radically different from that of the adult, for example, several metabolism or different route of the clearance.