Dosing information for children, unlike adults, is often presented as a mg/kg range. So how do you choose what dose to use?This recent discussion from the BMJ has some important take home messages .

Did you know that a child qualifies for an adult antibiotic dose usually by the time they weigh 40 kg?  That means that the mg/kg childhood dose x 40 = the adult dose. e.g. 25mg/kg = adult dose of 1 gram!. Paediatric doses should also be capped at adult doses, even if the calculation suggests using more!

Key messages from the BMJ paper-

• Methods for selecting dose of oral antibiotics in childhood must balance simplicity with accuracy

• Although using exact weight is most accurate, it requires a recent weight and may not fit with fixed dose formulations

• Age bands result in a substantial proportion of children receiving doses outside the recommended range and are context specific

• Weight banded dose selection is transferable across populations and the most practical choice when up to date weight is available