Understanding the rationale for metronidazole use in dogs and cats

J Small Anim Pract. 2025 Dec;66(12):909-917. doi: 10.1111/jsap.13910. Epub 2025 Jun 30.

Abstract

Objective: It is currently unknown how often antibiotics (including metronidazole) are used for non-antibacterial purposes in dogs and cats. This study looked to characterise the rationale for metronidazole prescription in these species.

Methods: Retrospective cohort study. Veterinarians reported clinical information for dogs and cats treated with metronidazole in the previous year, including the rationale for metronidazole selection.

Results: Three hundred and thirty-two cases were reported by 138 veterinarians describing metronidazole use in 47 cats and 285 dogs. Metronidazole was most commonly prescribed to treat acute diarrhoea (n = 156, 47%), chronic diarrhoea (n = 79, 24%) or giardiasis (n = 36, 11%). Veterinarians selected metronidazole exclusively for non-antimicrobial targeted therapy in 42% of cases (125/300). Putative anti-inflammatory/immunomodulatory properties were cited in 64% of cases (213/332). Educational resources (41/92, 45%), team-based collaboration (29/92, 32%) and specialist consultation (10/92, 11%) were cited as the supportive basis for these prescription choices.

Clinical significance: Veterinarians are using metronidazole frequently for non-antimicrobial properties in contradiction to antimicrobial use guidelines. Future stewardship programs should adapt guidance specifically to counter this prescribing behaviour.

MeSH terms

  • Animals
  • Anti-Infective Agents* / therapeutic use
  • Cat Diseases* / drug therapy
  • Cats
  • Cohort Studies
  • Diarrhea / drug therapy
  • Diarrhea / veterinary
  • Dog Diseases* / drug therapy
  • Dogs
  • Female
  • Giardiasis / drug therapy
  • Giardiasis / veterinary
  • Male
  • Metronidazole* / therapeutic use
  • Retrospective Studies

Substances

  • Metronidazole
  • Anti-Infective Agents