1802. Off-label Use of Antimicrobial Agents at the University Hospital for Infectious Diseases, Zagreb, Croatia

BACKGROUND: Antimicrobial agents' (AMAs) off-label use can be associated with the prescriber's education. Little is known about the AMAs' off-label use by infectious disease (ID) specialists. We have conducted research at the University Hospital for Infectious Diseases (UHID), Zagreb, Croatia, a 230-bed tertiary center where ID specialists primarily prescribe AMAs. METHODS: A retrospective cross-sectional analysis was conducted on the day with the highest hospitalization number, January 17, 2019. Any use of AMA not complying with the SmPC was considered off-label and evaluated regarding modality (indication, dose, regimen, route of administration, and age) and justification by institutional or/and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) guidelines. RESULTS: The study included 155 patients, 63 (40.6%) adults and 92 (59.4%) children. 61 (96.8%) adult patients had at least one AMA. There were 134 AMA prescriptions in adults, 42 (31.3%) off-label. AMAs were most frequently prescribed off-label regarding regimen (21), dose (17), and indication (14). Institutional guidelines justified off-label in 5 cases regarding dose, 4 regarding indication, and 2 regarding regimen. ESCMID guidelines justified off-label prescriptions in 5 cases regarding indication. The rest of the off-label was not supported by the existing guidelines. 60 (65.2%) pediatric patients had at least one AMA. There were 73 prescriptions, 31 (42.5%) off-label. AMAs were most frequently prescribed off-label regarding indication (19), dose (12), and age (2). Institutional guidelines justified 3 off-label cases regarding indication and 1 regarding dose. ESCMID guidelines justified no off-label in children. The lack of guidelines was the leading cause of the off-label AMAs use in children. CONCLUSION: One-third of AMAs are prescribed off-label regarding SmPC by ID specialists. However, institutional and international guidelines can justify part of this use. DISCLOSURES: All Authors: No reported disclosures.