London: A team of scientists and clinicians, led by researchers at King's College London and St George's, University of London, are calling for a review of penicillin dosing guidelines for children, as the current guidelines have remained unchanged for nearly 50 years.
The call comes as a study published in the British Medical Journal indicates some children may not be receiving effective doses, which could potentially lead to failed treatment and contribute to antibiotic resistance.
Oral penicillins (such as amoxicillin) account for nearly 4.5 million of the total 6 million annual prescriptions for antibiotics given to treat childhood bacterial infections each year in the UK.
Current dosing guidelines for penicillin are provided by the British National Formulary for Children (BNFC) and are mainly based on age bands.
The doses given have not changed in almost 50 years.
But the dose of penicillin needed is determined by a child's weight, and the guidelines have not taken into account the increase in the average weight of children over time.
The experts say reviewing these guidelines is essential, to ensure all children who require penicillin are receiving effective doses.
The review was led by Dr Paul Long from the Institute of Pharmaceutical Science at King's College London and Professor Mike Sharland at St George's, University of London on behalf of the improving Children's Antibiotic Prescribing Research Network (iCAP).
The team carried out a literature review of evidence, including all the historic archives of the Royal Pharmaceutical Society and the British Medical Association, to understand the origins of the current dosing guidelines.
They found that prescribing based on age bands had first been suggested in the early 1950s, based on the results of oral dosing studies.
Following these findings, a general recommendation to use age banding for all antibiotics in children was published in the BMJ in 1963, and these same recommendations remain in use today.
The researchers found that the age band guidelines set in 1963 were accompanied by average weights, and doses are based on fractions of the widely used adult doses.
The BNFC structured dosing bands are: birth to 1 year (10 kg); 2 years (13 kg); 5 years (18 kg); and 10 years (30 kg).
However, according to the Health Survey for England 2009, the average weight today of a 5 year old is 21 kg and a 10 year old is 37 kg, indicating that average weights today are up to twenty percent higher than in 1963.
Under-dosing is potentially a problem for children, as this could lead to sub-therapeutic concentrations.
The researchers also noted that adult penicillin recommendations have been re-evaluated taking modern weights into consideration, and penicillin doses have consequently increased.
But UK recommendations for children have not been reassessed in the same way.