Treatment of Bacterial Vaginosis
The CDC recommends metronidazole 500 mg orally twice daily for 7 days as the preferred first-line treatment for bacterial vaginosis, achieving a 95% cure rate. 1, 2, 3
First-Line Treatment Options
All three of the following regimens are CDC-recommended first-line options for non-pregnant women:
Metronidazole 500 mg orally twice daily for 7 days - This is the gold standard with superior efficacy (95% cure rate) compared to all alternative regimens 1, 2, 3
Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days - Equally effective as oral therapy but with fewer systemic side effects 1, 2, 4, 5
Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days - Another equally acceptable first-line option 1, 2, 3
Alternative Regimens (Lower Efficacy)
Use these only when first-line options are not feasible:
Metronidazole 2g orally as a single dose - Lower cure rate (84% vs 95%) but useful when compliance is a major concern 1, 2, 3
Clindamycin 300 mg orally twice daily for 7 days - Alternative when metronidazole cannot be used 1, 2, 3
Tinidazole 2g once daily for 2 days OR 1g once daily for 5 days - FDA-approved with therapeutic cure rates of 22-32% above placebo, though lower than metronidazole 6
Critical Patient Counseling
Alcohol avoidance is mandatory:
- Patients must avoid all alcohol during metronidazole treatment and for 24 hours after completion to prevent disulfiram-like reactions 1, 2, 3
Barrier contraception warning:
- Clindamycin cream and ovules are oil-based and weaken latex condoms and diaphragms for up to 5 days after use 1, 2, 3
Special Populations
Pregnant Women
For symptomatic pregnant women at high risk of preterm delivery (history of prior preterm birth):
- Metronidazole 250 mg orally three times daily for 7 days is the preferred treatment 1, 7
- Treatment may reduce risk of prematurity in high-risk women 2, 3
For symptomatic pregnant women at low risk:
First trimester considerations:
- Clindamycin vaginal cream is preferred if metronidazole is contraindicated 2
Patients with Metronidazole Allergy
- Clindamycin cream or oral clindamycin is the preferred alternative 2, 3
- Patients allergic to oral metronidazole should NOT receive metronidazole vaginally 2, 3
Breastfeeding Women
- Standard CDC guidelines apply - metronidazole is compatible with breastfeeding 2
- Small amounts excreted in breast milk are not significant enough to harm the infant 2
HIV-Infected Patients
- Treat with the same regimens as HIV-negative patients 2
Management Principles
Partner treatment is NOT recommended:
- Routine treatment of male sex partners has no effect on cure rates, relapse, or recurrence in clinical trials 1, 2, 3
Follow-up is unnecessary if symptoms resolve:
- No follow-up visits are needed when symptoms resolve 1, 2, 3
- Advise patients to return only if symptoms recur 2, 3
Special Clinical Situations
Pre-procedural screening and treatment is recommended:
- Screen and treat women with BV before surgical abortion or hysterectomy due to increased risk of postoperative infectious complications 1, 2
- Treatment with metronidazole reduces postabortion PID by 10-75% 1, 2
Recurrent Bacterial Vaginosis
For recurrent BV (up to 50% of women experience recurrence within 1 year):
- Extended metronidazole 500 mg orally twice daily for 10-14 days 8
- If ineffective, use metronidazole vaginal gel 0.75% for 10 days, followed by twice weekly for 3-6 months 8
Common Pitfalls to Avoid
- Do not use the single-dose 2g metronidazole regimen as first-line - it has an 11% lower cure rate than the 7-day regimen 1, 3
- Do not treat asymptomatic pregnant women at low risk for preterm delivery 1
- Do not forget to counsel about alcohol avoidance with metronidazole - this is a critical safety issue 1, 2, 3
- Do not waste resources treating male partners - it provides no benefit 1, 2, 3