The frequency and duration of side-effects associated with the use of oral metronidazole; A prospective study of VITA trial participants.

Abstract

ackground: The tolerability of metronidazole is often perceived as being poor and in particular as being a cause of gastrointestinal side effects, but the frequency, severity and duration of adverse effects (AE) is not well characterised. This study assessed the frequency and type of metronidazole associated AEs in women treated for bacterial vaginosis.

Methods: An exploratory study of participants from the lactic acid gel versus metronidazole for treating bacterial vaginosis (VITA) randomised controlled trial. In this sub-study, women aged ≥16 years, diagnosed with bacterial vaginosis and who received oral MTZ (400 mg twice daily, for 7 days) were followed up prospectively over 2 weeks. Baseline demographic and clinical data, and self-reported data on the incidence, time to onset, and duration of AEs were analysed.

Results: 155 women were included, of whom 64% (99/155) reported at least one metronidazole AE, including 47% (72/155) who reported gastrointestinal symptoms (nausea and/or vomiting [52/155], abdominal pain [31/154] or diarrhoea [31/154]) mostly within 3 days of starting treatment and resolving within 5 days of onset. Treatment discontinuation occurred in 8% (12/148) overall and AEs were given as the reason for discontinuing in only 3% (4/148).

Conclusion: Overall, metronidazole side effects occurred commonly, but resolved within a few days and had a limited impact on treatment completion.