Bacterial Vaginosis

Doses are oral and for adults unless otherwise stated. Visit the Health Products Regulatory Board website or the printed Irish Medicines Formulary for drug SPCs, dosage, contraindications, interactions, or IMF/BNF/BNFC/MIMS. See guidance on dosing in children for quick reference dosage/weight guide.

Letters indicate strength of evidence range from A+ (systematic review) to D (informal opinion). Statins can interact with some antibiotics and increase the risk of rhabdomyolysis. Amiodarone and drugs which prolong the QT interval can interact with many antibiotics. Many antibiotics increase the risk of bleeding with anticoagulants. Please refer to our Drug Interactions Table for further information.

Comments from Expert Advisory Committee

  1. Bacterial Vaginosis is a common cause of abnormal vaginal discharge in women of reproductive age

  2. It is characterised by a white, non-irritating, malodorous vaginal discharge. The discharge commonly smells "fishy" and this odour is often more noticeable after sexual intercourse
  3. The diagnosis can be made clinically on the basis of the description and appearance of the discharge. Typically the normal pH of the vagina is increased from normal (<4.5) to above 4.5 and up to 6.0 reflecting the replacement of normal lactobacilli with anaerobic organisms
  4. Consider sexually transmitted causes of vaginal discharge on the basis of sexual history and consider testing for chlamydia and gonorrhoea
  5. Treatment can be started without doing a high vaginal swab
  6. No benefit in treating male partners
  7. Women experiencing repeated episodes of Bacterial Vaginosis may benefit from using lactic acid vaginal gels to facilitate restoration of the normal vaginal flora. Preparations are available over the counter in pharmacies. Repeated episodes are more frequent in women who practice vaginal douching.


See guidance on dosing in children for quick reference dosage/weight guide.

Treatment Dose TX Duration Comment
metronidazoleA+ 400 mg BD 5-7 days

Advise patients of disulfuram reaction
with alcohol, prior to taking metronidazole

OR metronidazole 
0.75% vaginal gelA+
5g applicatorful at night 5 nights
OR clindamycin 2% creamA+ 5g applicatorful at night 7 nights

topical more expensive than
metronidazole but as effective

Useful Resources

Patient Information

We recommend patients use the website developed by HSE/ICGP/IPU partnership for tips on how to get better from common infections without using antibiotics, what you can do for yourself or a loved one and when to seek help.

The HSE Health A-Z website provides patient information on many hundreds of conditions and treatments.

Reviewed June 2017

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