192. More Low-hanging Fruit: Antibiotic Chelation Drug Interactions

Background Attainable, low-resource antimicrobial stewardship (AMS) interventions, “low-hanging fruit” can be facilitated by electronic medical record (EMR) enhancements. Oral (PO) fluoroquinolone (FQ) or tetracycline (TCN) coadministration with di- and tri-valent cations reduces antibiotic absorption by up to 75%, is common, and may represent low-hanging fruit. We evaluated concomitant administration and outcomes in a five hospital system before and after an EMR medication safety improvement. Methods IRB approved quasi-experiment, emergency (ED) visits and hospital admissions September 2016–February 2017 and September 2017–February 2018. Standard of Care: cations were scheduled 0900 and 2100; FQ and TCN administration instructions stated: “Administer at least 2 hours before or 6 hours after (cations).” Intervention: April 2017 EMR change in the default timing of FQ and TCN to 0630 and 1530 with pharmacy and nurse education. Primary endpoint: coadministration, defined as administration of PO product containing calcium, magnesium, iron, or phosphate binder 2 hours before or 6 hours after PO doxycycline, ciprofloxacin, or moxifloxacin. Results A total of 4,414 and 5,231 patients, representing 4,887 and 5,781 encounters, received PO FQ or TCN pre- and post-intervention, respectively. Average age (years) pre: 62.1, post: 61.3. Respiratory infection most common (25% pre, 27% post) followed by genitourinary (13% pre, 12% post). Concomitant administration: 3629/17,702, 20.5% pre vs. 2,184/20,524, 10.6% post (P < 0.001), see Table 1. Median hospital length of stay: 3 (0.3, 6) pre, 2.9 (0.3, 5.8) post. Thirty-day all-cause readmission: 28% pre and 27.2% post. Conclusion A system-based change to the EMR was effective to reduce the frequency of FQ and TCN chelation interactions by half and represents a low-hanging fruit strategy for AMS programs. Our institution has subsequently employed this strategy to reduce chelation interactions with HIV integrase inhibitors. Table 1: Coadministration by Antibiotic Pre-group Post-group Drug No. of Administrations No. (%) of Coadministrations No. of Administrations No. (%) of Coadministrations Ciprofloxacin 6,209 1,394 (22.5%) 6,721 787 (11.7%) Moxifloxacin 1,689 392 (23.2%) 1,378 168 (12.2%) Doxycycline 9,804 1,843 (18.8%) 12,425 1,229 (9.9%) Disclosures S. L. Davis, Achaogen: Scientific Advisor, Consulting fee. Allergan: Scientific Advisor, Consulting fee. Melinta: Scientific Advisor, Consulting fee. Nabriva: Scientific Advisor, Consulting fee. Zavante: Scientific Advisor, Consulting fee.