Determining the Accuracy of Weight-Based Dosing for Pediatric Antibiotics

Many pediatric prescriptions have a dose that is based on weight, which means that a patient’s current weight is necessary to ensure a proper dose. However, health care providers don’t need to share the patient’s weight with the prescription, which means that the weight found in the pharmacy dispensing system is often incorrect. A poster presented at the APhA 2022 Annual Meeting & Exposition in San Antonio, Texas, evaluated the completeness of information available to pharmacists at the time of dispensing and dosing error rate for antibiotic prescriptions for acute otitis media and acute pharyngitis.¹

Investigators conducted their study at a community pharmacy in rural Southeast Missouri—1 of only 4 pharmacies in the county, an area that is medically underserved and has a diverse population. Researchers conducted a retrospective chart review that included prescriptions written for patients aged 17 years and younger; were for antibiotics, including amoxicillin, amoxicillin/clavulanate, cefdinir, cephalexin, clindamycin, azithromycin, and clarithromycin; and had a diagnosis code for either acute otitis media or acute pharyngitis. Current treatment guidelines were used to assess medication and dose appropriateness.

A total of 115 prescriptions met inclusion criteria. Forty-five of the prescriptions did not have both a diagnosis code and weight included, with 11 missing the diagnosis code, 14 missing the patient weight, and 20 missing both. Of the 14 prescriptions missing weight, 13 were for acute otitis media and 1 was for acute pharyngitis.

Among the 70 prescriptions with complete information, 7 were for acute pharyngitis (2 inappropriate doses and 5 appropriate doses) while the other 63 were for acute otitis media (37 inappropriate doses and 26 appropriate doses).

Of the 42 prescriptions with complete information that were dosed inappropriately, the dosing errors were:

• Subtherapeutic dosing – 20 prescriptions
• Subtherapeutic dosing and incorrect frequency – 17 prescriptions
• Overdosage – 2 prescriptions
• Incorrect frequency – 2 prescriptions
• Overdosage and incorrect duration – 1 prescription

The investigators stated that their findings offer a baseline of dosing errors that can help build a framework to improve habits when prescribing antibiotics to pediatric patients. They urged further research into a wider array of pediatric antibiotics and disease codes to determine the accuracy of weight-based dosing.

Reference

1. Holder K, Guthrie K, Oprinovich S, Mize T. Evaluating pediatric weight-based antibiotic dosing in a community pharmacy. Presented at: American Pharmacists Association 2022 Annual Meeting & Exposition; March 18-21, 2022; San Antonio, TX.