Treatment of Chronic Bacterial Vaginosis
For chronic/recurrent bacterial vaginosis, treat with oral metronidazole 500 mg twice daily for an extended 10-14 day course, followed by suppressive metronidazole gel 0.75% twice weekly for 3-6 months to prevent recurrence. 1
Understanding Recurrent BV
Recurrence is extremely common, affecting approximately 50% of women within 12 months of initial treatment for incident disease. 1, 2 The high recurrence rate stems from:
- Biofilm formation on vaginal mucosa that protects BV-causing bacteria from antimicrobial therapy 1, 2
- Persistence of residual infection despite initial treatment 1
- Possible reinfection from sexual partners, though this remains controversial 1
Treatment Algorithm for Recurrent BV
First Recurrence
- Oral metronidazole 500 mg twice daily for 10-14 days (extended course beyond standard 7 days) 1
- Counsel patients to avoid alcohol during treatment and for 24 hours afterward to prevent disulfiram-like reactions 3, 4
If First Extended Course Fails
- Metronidazole gel 0.75%, one full applicator (5g) intravaginally twice daily for 10 days 1
- Followed immediately by suppressive therapy: metronidazole gel 0.75% twice weekly for 3-6 months 1
- This produces mean peak serum concentrations less than 2% of standard oral doses, minimizing systemic side effects 4
Alternative Regimens for Metronidazole Intolerance
- Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days 3, 4
- Cure rates comparable to metronidazole (78% vs. 82% in randomized trials) 4, 5, 6
- Critical warning: Oil-based formulation weakens latex condoms and diaphragms 3, 4
For True Metronidazole Allergy
- Never use metronidazole gel vaginally in patients with true oral metronidazole allergy 4, 7
- Use clindamycin cream 2% as described above 4
- Oral clindamycin 300 mg twice daily for 7 days achieves 93.9% cure rates 4
For Dual Allergy (Metronidazole AND Clindamycin)
- Tinidazole 1 g once daily for 5 days achieves 36.8% therapeutic cure 7, 8
- Alternative: tinidazole 2 g once daily for 2 days (27.4% therapeutic cure) 7, 8
- Patients must avoid alcohol during treatment and for 72 hours (not 24 hours) after the last dose 7
Critical Clinical Pitfalls
What NOT to Do
- Do not treat male sexual partners routinely - clinical trials consistently show this does not influence cure rates or reduce recurrence 3, 4, 1
- Do not use single-dose metronidazole 2g for recurrent BV - this has lower efficacy (84%) and is only appropriate for incident disease when compliance is a concern 3
- Do not use clindamycin vaginal cream in late pregnancy - increased adverse events including prematurity and neonatal infections 4
Important Counseling Points
- No follow-up visit is necessary if symptoms resolve 3, 4
- Recurrence rates remain high (approaching 50% within 1 year) regardless of antibiotic choice 4, 1, 2
- Patients should return for retreatment if symptoms recur 4
Special Populations
Pregnancy
- First trimester: Clindamycin vaginal cream only (metronidazole contraindicated) 4
- Second/third trimester: Metronidazole 250 mg orally three times daily for 7 days 3, 4
- Treatment may reduce preterm delivery risk in high-risk pregnant women 3, 9
Before Surgical Procedures
- Screen and treat women with BV before surgical abortion or hysterectomy due to increased risk of postoperative infectious complications 3
Emerging Considerations
While probiotics, prebiotics, and botanical treatments show some promise in initial studies, antimicrobial therapy remains the mainstay of treatment for recurrent BV. 1 Current evidence for alternative therapies (probiotics, vitamin C) is limited and insufficient to recommend as primary treatment. 9