The doctor has ordered an antibiotic whose average adult dose is 250 mg per
day. What would the dosage for this medication be on a child who is 100 cm
in length and weighs 25 kg? See the example below.

In this example, 115 mg of medication would be given.

Formula

First, the body surface area (BSA) must be determined:

kg^{0.425} x cm^{0.725} x 0.007184 =
BSA

The above formula is just one method for
determining BSA. Results with other formulas will vary.

Next, the following formula* is used:

BSA

x
adult dose = approx. child dose

1.73

*Gerald, M. C., & O’Bannon, F. V.
(1988). Nursing pharmacology and therapeutics. (2nd ed.). Englewood Cliffs, NJ:
Prentice Hall Incorporated.

Note: This web page is intended for educational purposes. Do not use this tool for clinical practice. This information is intended for nurses and nursing students. Nurses are traditionally taught to use a nomogram for estimating BSA. More accurate methods of pediatric dosing exist. Only persons licensed in administering medications may give medications. Also, not all drugs that are safe on adults may be given to children due to differences in physiology. Pets likewise do not share the same physiology as humans.