Treatment for Bacterial Vaginosis
Oral metronidazole 500 mg twice daily for 7 days is the preferred first-line treatment for bacterial vaginosis in non-pregnant women, achieving the highest cure rate of 95%. 1
First-Line Treatment Options
The CDC recommends three equally acceptable first-line regimens for non-pregnant women with bacterial vaginosis:
Oral metronidazole 500 mg twice daily for 7 days - This is the preferred regimen with the highest efficacy (95% cure rate) and should be your default choice 1, 2
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, achieving mean peak serum concentrations less than 2% of standard oral doses 1, 2, 3
Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days - Another effective first-line option with comparable cure rates (78-82%) 1, 2
Alternative Treatment Regimens
When compliance is a concern or first-line options are not suitable:
Oral metronidazole 2g single dose - Lower efficacy (84% cure rate) compared to the 7-day regimen, but useful when adherence is questionable 1, 2
Oral clindamycin 300 mg twice daily for 7 days - Alternative when metronidazole cannot be used, with cure rates of 93.9% 1, 2
Tinidazole 2g once daily for 2 days OR 1g once daily for 5 days - FDA-approved alternative with therapeutic cure rates of 27.4% and 36.8% respectively (using strict criteria requiring resolution of all 4 Amsel criteria plus Nugent score <4) 4
Critical Safety Precautions
Patients using metronidazole must avoid all alcohol during treatment and for 24 hours afterward to prevent disulfiram-like reactions (flushing, nausea, vomiting, headache). 1, 2, 5
Clindamycin cream and ovules are oil-based and will weaken latex condoms and diaphragms - counsel patients to use alternative contraception during treatment and for several days after completion. 1, 2
Special Populations
Patients with Metronidazole Allergy
Use clindamycin 2% vaginal cream, one full applicator (5g) intravaginally at bedtime for 7 days as the preferred first-line alternative 2
Oral clindamycin 300 mg twice daily for 7 days is equally effective (93.9% cure rate) 2
Never administer metronidazole gel vaginally to patients with true metronidazole allergy - true allergy requires complete avoidance of all metronidazole formulations 2
Patients with metronidazole intolerance (not true allergy) can potentially use metronidazole vaginal gel due to minimal systemic absorption 2
Pregnancy
First trimester: Clindamycin vaginal cream is the ONLY recommended treatment - metronidazole is contraindicated 1, 2, 5
Second and third trimesters: Metronidazole 250 mg orally three times daily for 7 days is the recommended regimen 1, 2, 5
All symptomatic pregnant women should be tested and treated for BV 1, 5
Treatment in high-risk pregnant women (history of preterm delivery) may reduce risk of prematurity 1
Systemic therapy is preferred over topical therapy during pregnancy to treat possible subclinical upper genital tract infections 5
Avoid clindamycin vaginal cream in later pregnancy due to increased adverse events including prematurity and neonatal infections 2
Breastfeeding Women
Standard CDC guidelines apply - metronidazole is considered compatible with breastfeeding 1
Small amounts of metronidazole are excreted in breast milk but not significant enough to harm the infant 1
Intravaginal preparations minimize systemic absorption and are preferred if systemic side effects are a concern 1
HIV-Infected Patients
- Patients with HIV and BV should receive the same treatment as persons without HIV 1
Follow-Up Management
Follow-up visits are unnecessary if symptoms resolve 1, 2, 5
Patients should return for additional therapy if symptoms recur 1
Routine treatment of male sex partners is NOT recommended - clinical trials demonstrate that treating partners does not influence treatment response or reduce recurrence rates 1, 2, 5, 6
Important Clinical Considerations
When to Screen and Treat Asymptomatic BV
Before surgical abortion or hysterectomy - screening and treating women with BV is recommended due to increased risk for postoperative infectious complications 1, 5
Treatment of BV with metronidazole has been shown to substantially reduce post-abortion PID 1
Common Pitfalls to Avoid
Do not use metronidazole gel for trichomoniasis - it is not effective despite being effective for BV 5
Metronidazole may cause gastrointestinal upset and unpleasant metallic taste; intravaginal preparations have fewer systemic side effects 1, 2
Recurrence rates approach 50% within 1 year of treatment - counsel patients accordingly 2