Treatment of Bacterial Vaginosis in Male Partners
Male partners of women with bacterial vaginosis should be treated with metronidazole 400 mg orally twice daily for 7 days plus 2% clindamycin cream applied to penile skin twice daily for 7 days to reduce BV recurrence in their female partners. 1
The Paradigm Shift in Male Partner Treatment
This recommendation represents a significant departure from historical guidelines. For decades, CDC guidelines explicitly stated that treating male partners was not beneficial and should not be done 2, 3. However, a landmark 2025 randomized controlled trial published in the New England Journal of Medicine fundamentally changed this approach 1.
The Evidence That Changed Practice
- The StepUp trial demonstrated that concurrent male partner treatment reduced BV recurrence from 63% to 35% over 12 weeks (absolute risk reduction of 28%, P<0.001) 1
- This trial was stopped early by the data safety monitoring board because treating women alone was clearly inferior to treating both partners 1
- The recurrence rate dropped from 4.2 per person-year in controls to 1.6 per person-year with partner treatment 1
Treatment Protocol for Male Partners
Combination oral and topical therapy is essential:
- Oral metronidazole 400 mg twice daily for 7 days 1, 4, 5
- 2% clindamycin cream applied to penile skin twice daily for 7 days 1, 4, 5
The combination approach targets both the penile skin and urethral microbiota, where BV-associated bacteria colonize and can reinfect female partners 6.
Critical Patient Instructions
Alcohol avoidance is mandatory:
- Patients must avoid all alcohol during metronidazole treatment and for 24 hours after completion to prevent disulfiram-like reactions (severe nausea, vomiting, flushing, tachycardia) 4, 7, 5
Sexual activity restrictions:
- Couples should refrain from unprotected intercourse for at least 14 days to allow treatment to take full effect 4, 5
Expected Adverse Effects
Male partners may experience:
These effects are generally well-tolerated, with high adherence rates demonstrated in clinical trials 1, 6.
Microbiological Rationale
The treatment works by targeting BV-associated bacteria at multiple male genital sites:
- Penile skin harbors BV-associated bacteria that can be sexually transmitted back to female partners 6
- The male urethra also serves as a reservoir for these organisms 6
- Combination therapy immediately and significantly reduces BV-associated bacteria at both sites 6
Follow-Up Considerations
- No routine follow-up is needed for asymptomatic male partners 4, 5
- Women should return if symptoms persist or recur after treatment 5
- For pregnant women with BV, follow-up evaluation one month after treatment completion is recommended 5
Important Clinical Caveats
This applies specifically to heterosexual couples in monogamous relationships where the female partner has recurrent or incident BV 1. The evidence base for this recommendation comes from Australian populations, and applicability to broader populations requires further study 8.
Historical context matters for patient counseling: Many patients and providers may have been previously told that BV is not sexually transmitted and that partner treatment is unnecessary 2, 8. The 2025 evidence directly contradicts these older recommendations, requiring updated patient education 8, 1.