Routine antibiotic therapy in the management of the local inflammatory swelling in venomous snakebites: results of a placebo-controlled study

Abstract

Objective: To evaluate the value of routine antibiotic therapy in the management of the local swelling of patients with venomous snakebites.

Methods: A prospective, placebo-controlled study at the General Hospital, Anuradhapura, Sri Lanka where 144 patients with envenoming and local swelling in the leg were allocated to receive either antibiotics (Group A = test group) or placebo (Group B = controls). Benzyl penicillin 2 mega units intravenously 6 hourly and metronidazole 500 mg by intravenous infusion 8 hourly for 5 days from the first day of the bite were given to Group A. Ethical committee approval was obtained from the Committee of General Hospital, Anuradhapura.

Main outcome measures: Circumference difference between the affected limb and the normal limb, length of the swelling measured in centimetres, and the physical characteristics of the local swelling of both groups were compared.

Results: Group A had 69 patients and the Group B 75. The mean circumference difference (MCD) of the leg between the groups showed no significant difference for 4 days (P > 0.05), except at the site of the bite on the third day when the Group B showed a significant improvement (p = 0.02). There was no significant difference in the length of the local swelling or the score of physical characteristics between the two groups (P > 0.05). The proportions of recovery of the local swelling on the fourth and fifth day had no significant difference between the groups (P > 0.05).

Conclusion: The routine use of antibiotics (penicillin and metronidazole) does not seem to be of value in reducing the local inflammatory swelling in venomous snakebite.