Changing Trends in Oral Antimicrobial Use in the Emergency Department following the Introduction of Cephalexin and Amoxicillin/clavulanic Acid to the Hospital Formulary

The National Action Plan on Antimicrobial Resistance was implemented by the Ministry of Health, Labor and Welfare in Japan in 2016. The aim is to reduce the use of broad spectrum antibacterial drugs and optimize the use of oral antimicrobials. Ogaki Municipal Hospital has been promoting the use of cephalexin (CEX) and the combination of amoxicillin and clavulanate potassium (AMPC/CVA) since these drugs were added to the drug formulary in December 2012. In this study, we compared trends in oral antibiotic use in the emergency department before and after the addition of CEX and AMPC/CVA to the formulary. We observed a significant decrease in the average monthly consumption of third-generation cephalosporins (before: 264.3 ± 58.2 days; after: 108.5 ± 35.2 days; P < 0.01), and of macrolides (before: 52.7 ± 21.9 days; after: 18.9 ± 13.7 days; P < 0.01). Cost savings on oral antibiotics following the formulary revisions were calculated as 500,000 yen over three years. No difference in clinical effect was observed when comparing CEX, AMPC/CVA, and a third-generation cephalosporin. Therefore, we recommended the use of CEX and AMPC/CVA, according to the hospital formulary, in order to change trends in oral antibiotic use and achieve the objectives of the National Action Plan on Antimicrobial Resistance.