Randomized clinical trial of metronidazole ointment versus placebo in perianal Crohn's disease

Br J Surg. 2010 Sep;97(9):1340-7. doi: 10.1002/bjs.7121.


Background: The potential for metronidazole 10 per cent ointment to exert therapeutic benefit in perianal Crohn's disease, while minimizing the adverse effects found with oral metronidazole, was evaluated in a randomized placebo-controlled study.

Methods: Subjects with perianal Crohn's disease were randomized to metronidazole 10 per cent ointment, 0.7 g applied perianally three times daily, or placebo ointment. The Perianal Crohn's Disease Activity Index (PCDAI) was scored at baseline and after 4 weeks of treatment. Perianal pain was assessed on a visual analogue scale.

Results: Seventy-four subjects (33 metronidazole, 41 placebo) were evaluated. The mean(s.e.m.) reduction in PCDAI score at 4 weeks was 2.4(0.5) in the metronidazole group and 2.2(0.4) in the placebo group (P = 0.660). More subjects in the metronidazole group than the placebo group showed a reduction in PCDAI score of at least 5 points (10 of 27 versus 4 of 34; P = 0.031). Perianal discharge was reduced significantly in metronidazole-treated subjects (P = 0.012). A greater reduction in perianal pain was seen in the metronidazole group, which approached statistical significance (P = 0.059). No serious adverse events were reported.

Conclusion: Metronidazole 10 per cent ointment was not effective in the reduction of PDCAI score, but some secondary outcomes showed improvement suggestive of a treatment effect. It is well tolerated, with minimal adverse effects, and has potential as treatment for pain and discharge associated with perianal Crohn's disease.

Registration number: NCT00509639 (http://www.clinicaltrials.gov).

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Topical
  • Adult
  • Anti-Bacterial Agents / administration & dosage*
  • Anti-Bacterial Agents / adverse effects
  • Anus Diseases / drug therapy*
  • Crohn Disease / drug therapy*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Metronidazole / administration & dosage*
  • Metronidazole / adverse effects
  • Ointments
  • Pain / prevention & control
  • Patient Satisfaction
  • Quality of Life
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Ointments
  • Metronidazole

Associated data

  • ClinicalTrials.gov/NCT00509639