National Amoxicillin-Clavulanate Formulation Use Pattern: A Survey.

Objective: Five commercially available amoxicillin-clavulanate (AMC) ratio formulations contribute to ratio selection variability with efficacy and toxicity implications. The objective of this survey was to determine AMC formulation use patterns across the United States.

Methods: A multicenter practitioner survey was distributed to multiple listservs (American College of Clinical Pharmacy pediatrics, infectious diseases, ambulatory care, pharmacy administration; American Society of Health-System Pharmacists; Pediatric Pharmacy Association members), and selected pediatric Vizient members in June 2019. Responses were screened for multiples within institutions. Repeated organization responses were identified (n = 37) and excluded if the duplicate matched another response from the same organization exactly (n = 0).

Results: One hundred ninety independent responses were received. Nearly 62% of respondents represented a children's hospital within an acute care hospital; remainder being from stand-alone children's hospitals. Around 55% of respondents indicated prescribers were responsible for choosing the patient-specific formulation for inpatients. Nearly 70% of respondents indicated multiple formulations were available due to clinical need (efficacy, toxicity, measurable volume), whereas over 40% responded that the number of liquid formulations were limited to decrease the potential for error. Variability was demonstrated among institutions using ≥ 2 different formulations for acute otitis media (AOM), sinusitis, lower respiratory tract infection, skin and soft tissue infection, and urinary tract infection (33.6%, 37.3%, 41.5%, 35.8%, and 35.8%, respectively). The 14:1 formulation was the most common, but not exclusive, for AOM, sinusitis, and lower respiratory tract infections with 2.1%, 2.1%, and 2.6% of respondents indicating use of the 2:1 formulation and 10.9%, 15%, and 16.6% of respondents indicating use of the 4:1 formulation.

Conclusions: Significant AMC formulation selection variability exists across the United States.