Antibiotic doses for kids need review

Penicillin dosing guidelines need to be reviewed, British scientists say, to avoid serious health issues and antibiotic resistance.
Current dosing guidelines are based on a child’s weight in some cases, and a child’s age in others. (iStock)

Penicillin dosing guidelines for children need to be reviewed to avoid serious health issues and antibiotic resistance, British scientists say.

In an article published in the Thursday issue of the British Medical Journal, scientists argue that after 50 years of the same recommendations, British guidelines need to be standardized.

Current dosing is based on a child’s weight in some cases, and a child’s age in others. The authors argue this makes it confusing for physicians, resulting in underdosing. That's when a child fails to receive a large-enough dose to kill the harmful bacteria causing their illness. It can happen when a child's weight is higher than average for their age.

"Based on the results of oral dosing studies conducted using the scheme for penicillin G described at the conference,  a general recommendation to use age banding for all antibiotics in children, irrespective of the type of penicillin or disease indication, was published in the BMJ in 1963," reads the piece. "Critically, these recommendations have remained unchallenged and unchanged to this day."

Conversely, adult doses of penicillin have increased over the years.

"It's much more appropriate to dose by weight," Dr. Jeremy Friedman, pediatrician and head of the division of pediatric medicine at SickKids in Toronto, told CBC News. He says that large pediatric centres like Sick Kids rely on their own formulary which measures doses by weight, not age. However, he says some physicians who treat children — but who don't focus on them exclusively — may rely more often on standard dosing guidelines which are based on age. "It would not be infrequent for us to see a patient getting too low a dose or too high a dose," he says of patients he sees at the hospital.

The authors believe that if guidelines remain unchanged some children’s infections will  worsen, putting them at risk of serious complications.  Consequently, they will have to take additional courses of antibiotics. As well, because of underdosed children, the problem of antibiotic resistance will increase, leading to the need for more powerful and costly antibiotics.

Friedman says that more awareness is needed among physicians in Canada when it comes to prescribing antibiotics to children.

Currently the guidelines are piecemeal, with larger centres prescribing by weight and smaller centres or individual physicians relying on the Compendium of  Pharmaceuticals and Specialties, a reference book that guides healthcare professionals on how to prescribe and use drugs safely and appropriately —but that relies on more generalized guidelines when it comes to prescribing for children, according to Friedman. "It really boils down to educating people who prescribe to kids," he said.

The authors of the British piece also believe that physicians need to be more judicious in prescribing penicillin in the first place — something that Friedman supports.

"Not only do we need to determine the effective doses for children of all ages and weights but we also need to establish more clearly which children really need antibiotics in the era of pneumococcal conjugate (PCV 13), Haemophilus influenzae B, and meningitis C vaccines,"  they write.