Treatment for Bacterial Vaginosis
Metronidazole 500 mg orally twice daily for 7 days is the recommended first-line treatment for bacterial vaginosis, with cure rates of approximately 95%. 1, 2
Diagnosis
Bacterial vaginosis (BV) is diagnosed when at least three of the following Amsel criteria are present:
- Homogeneous, white, non-inflammatory discharge that adheres to vaginal walls 1, 2
- Presence of clue cells on microscopic examination 1, 2
- Vaginal fluid pH greater than 4.5 1, 2
- Fishy odor of vaginal discharge before or after addition of 10% KOH (whiff test) 1, 2
Alternatively, Gram stain of vaginal smear can be used to determine the relative concentration of bacterial morphotypes characteristic of BV 1, 3
First-Line Treatment Options
- Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) 1, 2
- Metronidazole gel 0.75%, one full applicator (5g) intravaginally twice daily for 5 days 1, 2, 4
- Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days 1, 2
Alternative Treatment Options
- Metronidazole 2g orally in a single dose (84% cure rate) - useful when compliance is a concern 1, 2
- Clindamycin 300 mg orally twice daily for 7 days 1, 2
- Tinidazole 2g once daily for 2 days or 1g once daily for 5 days 5
Treatment Considerations
- Patients using metronidazole should avoid alcohol during treatment and for 24 hours afterward due to potential disulfiram-like reaction 1, 2
- Clindamycin cream is oil-based and might weaken latex condoms and diaphragms 3
- Treatment of male sex partners has not been shown to alter the clinical course or reduce recurrence rates of BV 1, 2, 6
- Only women with symptomatic disease require treatment, as the principal goal of therapy is to relieve vaginal symptoms 1, 3
Special Populations
Pregnancy
- During first trimester: Clindamycin vaginal cream is preferred due to contraindication of metronidazole 1
- During second and third trimesters: Oral metronidazole can be used 1
Before Invasive Procedures
- Consider treatment of BV (symptomatic or asymptomatic) before surgical abortion procedures to reduce risk of post-abortion PID 1, 3
- Treatment before hysterectomy or other invasive gynecological procedures may reduce risk of postoperative infectious complications 3
Management of Recurrent BV
- Recurrence of BV is common, affecting 50-80% of women within one year of treatment 7, 8
- For recurrent BV, an extended course of metronidazole treatment (500 mg twice daily for 10-14 days) is recommended 7
- If ineffective, metronidazole vaginal gel 0.75% for 10 days, followed by twice weekly for 3-6 months, is an alternative regimen 7
- Adjunctive therapy with probiotics may improve cure rates when combined with antibiotics 9
Clinical Pitfalls to Avoid
- Failing to distinguish BV from other causes of vaginitis (trichomoniasis, vulvovaginal candidiasis) 2, 4
- Treating asymptomatic women unnecessarily, except before invasive procedures 1, 3
- Treating male partners, which has not been shown to prevent recurrence 1, 2, 6
- Inadequate treatment duration, which may lead to persistence and recurrence 10, 11