Available data from both a meta-analysis and cohort studies consistently demonstrated no statistically significant differences in clinical outcomes between metronidazole 500 mg IV administered every 12 hours versus every 8 hours. Across varied infection types, including anaerobic bacteremia and post-surgical prophylaxis, 12-hour dosing showed comparable rates of clinical cure, hospital length of stay, and mortality. Overall, these findings suggest that Q12H dosing may be clinically non-inferi...
A 2016 poster abstract details a retrospective chart review (N= 81) comparing metronidazole 500 mg twice daily (BID) versus three times daily (TID) for appendicitis or diverticulitis. Clinical outcomes and readmission rates were assessed at 30 days follow-up. Patients were excluded if they had concomitant infection, fistula, or chronic appendicitis. The authors did not find a statistical difference in resolution rates (values unspecified). The 30-day readmission rates were similarly nonsignificant with only 1 or 0 patients in the appendicitis or diverticulitis BID and TID groups being readmitted (p= 1 when comparing appendicitis and p= 0.417 when comparing diverticulitis). Yet, due to the small sample size and retrospective nature of the study, stronger evidence is needed to confirm these findings. [1]
Despite the limited clinical outcomes regarding Q12H vs Q8H metronidazole dosing, relatively dated pharmacokinetic (PK)/pharmacodynamic (PD) studies have observed efficient blood l...
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A search of the published medical literature revealed
3 studies investigating the researchable question:
What is the clinical efficacy of metronidazole 500 mg IV q12 hours when compared to metronidazole 500 mg IV q8 hours?
Level of evidence
B - One high-quality study or multiple studies with limitations
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[1] Béïque L, Tsang C, Geertsema S, et al. Comparison of metronidazole q12h to q8h in combination with other antibiotics on the clinical outcome and readmission rate of patients with appendicitis and diverticulitis. Open Forum Infectious Diseases. 2016;3(suppl_1):1037.
[2] Lamp KC, Freeman CD, Klutman NE, Lacy MK. Pharmacokinetics and pharmacodynamics of the nitroimidazole antimicrobials. Clin Pharmacokinet. 1999;36(5):353-373. doi:10.2165/00003088-199936050-00004
[3] Sprandel KA, Drusano GL, Hecht DW, Rotschafer JC, Danziger LH, Rodvold KA. Population pharmacokinetic modeling and Monte C...