Relationship between drug formulary and frequently used cephalosporins, macrolides and quinolones in Japanese hospitals

In Japan, hospitals' pharmaceutical affairs committees freely select the drugs to be purchased depending on the regulations of each hospital. This system poses a risk of the absence of essential drugs or an excess of similar drugs, and may promote inappropriate use of third-generation cephalosporins (3GCs) and quinolones. Against this backdrop, we researched availability of antibacterial agents in Japanese hospitals. We conducted a questionnaire-based study in eastern Shizuoka Prefecture, Japan. Questionnaires were sent to 33 hospitals that had established an interactive regional partnership on infection control. We analyzed the number of available oral cephalosporins, macrolides, and quinolones in each hospital, and the correlation between the number of total available antibacterial agents and the hospital scale and cephalexin availability. Thirty-one hospitals participated in this study. First-generation cephalosporin (1 GC) was available in only 22.5% of them. In all participating hospitals, 3GCs were available, with more than one 3 GC available in 74.2%. Quinolones were available in all hospitals, and more than one quinolone in 67.7%. The numbers of hospital beds and total available antibacterial agents were positively correlated and hospitals that owned cephalexin available also significantly more often owned other available antibacterial agents. 1 GC were available in only a few hospitals, while multiple 3GCs and quinolones were available in most. This situation may lead to excess use of 3GCs or quinolones in Japan. A low number of available drugs was associated with cephalexin unavailability. Outpatient antimicrobial stewardship may focus not only on the quality of medicine, but also on the prescribing environment.