What is the treatment for bacterial vaginosis?

Treatment of Bacterial Vaginosis

Oral metronidazole 500 mg twice daily for 7 days is the preferred first-line treatment for bacterial vaginosis, achieving cure rates up to 95%. 1, 2

First-Line Treatment Regimens

The CDC recommends three equally acceptable first-line options for non-pregnant women 3:

• Metronidazole 500 mg orally twice daily for 7 days - This achieves the highest cure rates (95%) and should be your default choice 1, 2
• Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days - Equally efficacious as oral therapy but with fewer systemic side effects (mean serum levels <2% of oral dosing) 1, 2
• Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days - Effective alternative but appears slightly less efficacious than metronidazole regimens 3, 2

Alternative Regimens (Lower Efficacy)

Use these only when compliance is a major concern or first-line options fail 3:

• Metronidazole 2g orally as single dose - Lower efficacy (84% cure rate vs 95% for 7-day regimen), but useful when adherence is questionable 1, 2
• Clindamycin 300 mg orally twice daily for 7 days - Reserve for metronidazole intolerance 3, 2
• Clindamycin ovules 100g intravaginally once at bedtime for 3 days - Another alternative option 3
• Tinidazole 2g once daily for 2 days OR 1g once daily for 5 days - FDA-approved with therapeutic cure rates of 27-37% (though measured by stricter criteria than older studies) 4

Critical Treatment Precautions

Patients must avoid all alcohol during metronidazole treatment and for 24 hours after completion due to disulfiram-like reaction risk 3, 1, 2

Clindamycin cream and ovules are oil-based and will weaken latex condoms and diaphragms - counsel patients accordingly 3, 1, 2

Special Populations

Pregnancy

All symptomatic pregnant women must be tested and treated due to associations with preterm rupture of membranes, preterm labor, and postpartum endometritis 3, 1

• Metronidazole 250 mg orally three times daily for 7 days is the recommended regimen for pregnant women 1, 5
• Systemic therapy is preferred over topical agents to treat possible subclinical upper genital tract infection 3, 5
• Avoid clindamycin cream in pregnancy - three trials showed increased adverse events including prematurity and neonatal infections 3

Allergy or Intolerance to Metronidazole

Use clindamycin cream or oral clindamycin as the preferred alternative 1, 2

Never give metronidazole vaginal gel to patients with oral metronidazole allergy - the allergy applies to both routes 3, 2

Breastfeeding

Standard CDC guidelines apply to breastfeeding women, as metronidazole is compatible with breastfeeding despite small amounts in breast milk 2

Intravaginal preparations minimize systemic exposure and are preferred if the patient has concerns 2

Pre-Procedural Treatment

Screen and treat women with BV before surgical abortion or hysterectomy, even if asymptomatic 3, 2

Treatment with metronidazole substantially reduces post-abortion PID by 55-75% in randomized trials 3, 2

Follow-Up and Recurrence

Follow-up visits are unnecessary if symptoms resolve 3, 1

Recurrence is common (50-80% within one year) - advise patients to return if symptoms recur and use an alternative regimen for recurrent disease 3, 6, 7

For recurrent BV, consider extended metronidazole 500 mg twice daily for 10-14 days, or if ineffective, metronidazole gel 0.75% for 10 days followed by twice weekly for 3-6 months 6

No long-term maintenance regimen is recommended 3

Partner Management

Do not routinely treat male sex partners - multiple clinical trials demonstrate that partner treatment does not affect cure rates or reduce recurrence 3, 1, 5

Common Pitfalls

• Do not use single-dose metronidazole 2g as first-line - the 11% lower cure rate (84% vs 95%) is clinically significant 1, 2
• Do not prescribe metronidazole 750mg extended-release tablets - no published data support clinical equivalency with standard regimens 3
• Do not use lactobacilli suppositories or douching - no data support efficacy 3
• Avoid topical clindamycin in pregnancy due to documented harm in three randomized trials 3