1037. Comparison of Metronidazole q12h to q8h in Combination with Other Antibiotics on the Clinical Outcome and Readmission Rate of Patients with Appendicitis and Diverticulitis.
Session: Poster Abstract Session: Antibiotic Stewardship: General Acute Care Implementation and Outcomes
Friday, October 28, 2016
Room: Poster Hall
  • Beique et al. Metronidazole q12h in appendicitis and diverticulitis.pdf (212.3 kB)
  • Background:

    Pharmacokinetic, pharmacodynamic and limited published clinical data support the administration of metronidazole in a twice daily (q12h) regimen versus three times daily (q8h).  As part of an Antimicrobial Stewardship initiative, we started promoting this change in practice in March 2015 during weekly rounds with the General Surgery team.  

    The objectives of this study are to determine if metronidazole 500 mg q12h differs from q8h in patients with appendicitis or diverticulitis, regarding 30-day clinical outcomes and readmission rates.


    A retrospective chart review of patients admitted with appendicitis or diverticulitis prior to, and after March 2015 was conducted. Patients prescribed a metronidazole-based regimen were assessed for clinical outcomes and readmission rates at 30 days.  Charts were excluded if patients were already taking metronidazole on admission, prescribed metronidazole q12h and q8h during the same admission, prescribed only one dose of metronidazole, admitted with a concomitant infection, or if they had a fistula or chronic appendicitis.


    Of 200 patients with appendicitis, 45 were included, and of 120 patients with diverticulitis, 36 were included. The primary reason for exclusion was not receiving metronidazole, or receiving only one dose. 82% of patients with appendicitis were treated surgically, and 92% of patients with a diverticulitis were treated conservatively.


    No statistical difference between the two groups was found for resolution rate. The 30-day readmission rate also did not differ between groups: 1/20 patients with appendicitis treated with q12h and 1/25 treated with q8h (p=1.00), 1/15 patients with diverticulitis treated with q12h and 0/21 treated with q8h (p=0.417). 

    Limitations of this study include the small sample size and its observational design.


    This retrospective chart review suggests that metronidazole q12h does not differ from metronidazole q8h with respect to 30-day clinical outcomes and readmission rates of patients with appendicitis or diverticulitis. A larger sample size and more indications are being assessed.


    Lizanne Béïque, BPharm, PharmD1,2, Corey Tsang, BScPhm1, Stephanie Geertsema, BScPhm1, Rosemary Zvonar, BScPhm, ACPR, FCSHP1, Caroline Nott, MBBS, FRCPC1,3, Janet Squires, RN, PhD2,4 and Kathryn Suh, MD, MSc, FRCPC1,3, (1)The Ottawa Hospital, Ottawa, ON, Canada, (2)The Ottawa Hospital Research Institute, Ottawa, ON, Canada, (3)Department of Medicine, University of Ottawa, Ottawa, ON, Canada, (4)School of Nursing, University of Ottawa, Ottawa, ON, Canada


    L. Béïque, None

    C. Tsang, None

    S. Geertsema, None

    R. Zvonar, None

    C. Nott, None

    J. Squires, None

    K. Suh, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.