192. More low-hanging fruit: antibiotic chelation drug interactions
Session: Poster Abstract Session: Antimicrobial Stewardship: Interventions Leveraging the Electronic Health Record
Thursday, October 4, 2018
Room: S Poster Hall
  • MoreLowHangingFruit_IDWeek2018FINAL.pdf (177.1 kB)
  • 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 5 hospital system before and after an EMR medication safety improvement.

    Methods: IRB approved quasi-experiment, emergency (ED) visits and hospital admissions 09/16–02/17 and 09/17–02/18. 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: 4414 and 5231 patients, representing 4887 and 5781 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: 3629/17702, 20.5% pre vs. 2184/20524, 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. 30 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





    # of administrations

    # (%)  of coadministrations

    # of administrations

    # (%)  of coadministrations



    1,394 (22.5%)


    787 (11.7%)



    392 (23.2%)


    168 (12.2%)



    1,843 (18.8%)


    1,229 (9.9%)


    Rachel M Kenney, PharmD1, Charles T Makowski, PharmD1, Brian Church, PharmD2 and Susan L Davis, PharmD3, (1)Henry Ford Hospital, Detroit, MI, (2)Henry Ford Health System, Detroit, MI, (3)Pharmacy Practice, Wayne State University, Detroit, MI


    R. M. Kenney, None

    C. T. Makowski, None

    B. Church, None

    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 .

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.