Oral penicillin prescribing for children in the UK: a comparison with BNF for Children age-band recommendations.

Background: The British National Formulary for Children (BNFC) recommends dosing oral penicillins according to age-bands, weight-bands, or weight-based calculations. Because of the rising prevalence of childhood obesity, age-band-based prescribing could lead to subtherapeutic dosing.

Aim: To investigate actual oral penicillin prescribing by GPs in the UK with reference to the current BNFC age-band recommendations.

Design And Setting: Descriptive analysis of UK prescriptions in the 2010 IMS Disease-Analyzer database (IMS-DA).

Method: A detailed database analysis was undertaken of oral penicillin prescriptions for 0-18 year olds from the 2010 IMS-DA. The prescription analysis included all available data on formulation, strength (mg), prescription quantity unit, package size, prescribed quantity, and volume.

Results: Considering amoxicillin alone, no infants (aged <1 year) were prescribed the BNFC 2011 edition recommended unit dose (62.5 mg), while the majority received double the dose (125 mg); among children aged 1-5 years, 96% were prescribed the recommended unit dose (125 mg), but 40% of 6-12 year olds and 70% of 12-18 year olds were prescribed unit doses below the BNFC recommendations. For otitis media, only those children aged <1 year received the recommended dose of amoxicillin (40-90 mg/kg/day). Similar variations in dosing across age-bands were observed for phenoxymethylpenicillin and flucloxacillin.

Conclusion: There is wide variation in the dosing of penicillins for children in UK primary care, with very few children being prescribed the current national recommended doses. There is an urgent need to review dosing guidelines, in relation to the weights of children today.