A systematic review of the role of penicillin versus penicillin plus metronidazole in the management of peritonsillar abscess

Abstract Background Peritonsillar abscess is a localised infection in the peritonsillar space. Pus from the abscess can contain anaerobes. Many clinicians prescribe metronidazole in addition to penicillin, but evidence to support this is limited. This review assessed the evidence of benefit of metronidazole for the treatment of peritonsillar abscess. Methods A systematic review was conducted of the literature and databases including Ovid Medline, Ovid Embase, PubMed and Cochrane library. Search terms included all variations of peritonsillar abscess, penicillin and metronidazole. Results Three randomised, control trials were included. All studies assessed the clinical outcomes after treatment for peritonsillar abscess, including recurrence rate, length of hospital stay and symptom improvement. There was no evidence to suggest additional benefit with metronidazole, with studies suggesting increased side effects. Conclusion Evidence does not support the addition of metronidazole in first-line management of peritonsillar abscess. Further trials to establish optimum dose and duration schedules of oral phenoxymethylpenicillin would benefit clinical practice.