Does single application of topical chloramphenicol to high risk sutured wounds reduce incidence of wound infection after minor surgery? Prospective randomised placebo controlled double blind trial.

Objective: To determine the effectiveness of a single application of topical chloramphenicol ointment in preventing wound infection after minor dermatological surgery.

Design: Prospective randomised placebo controlled double blind multicentre trial.

Setting: Primary care in a regional centre in Queensland, Australia.

Participants: 972 minor surgery patients.

Interventions: A single topical dose of chloramphenicol (n=488) or paraffin ointment (n=484; placebo).

Main Outcome Measure: Incidence of infection.

Results: The incidence of infection in the chloramphenicol group (6.6%; 95% confidence interval 4.9 to 8.8) was significantly lower than that in the control group (11.0%; 7.9 to 15.1) (P=0.010). The absolute reduction in infection rate was 4.4%, the relative reduction was 40%, and the relative risk of wound infection in the control group was 1.7 (95% confidence interval 1.1 to 2.5) times higher than in the intervention group. The number needed to treat was 22.8.

Conclusion: Application of a single dose of topical chloramphenicol to high risk sutured wounds after minor surgery produces a moderate absolute reduction in infection rate that is statistically but not clinically significant. Trial registration Current Controlled Trials ISRCTN73223053.