What is the treatment for bacterial vaginosis (BV) in male partners?

Treatment of Bacterial Vaginosis in Male Partners

Direct Recommendation

Male partners of women with bacterial vaginosis should receive combined oral metronidazole 400 mg twice daily for 7 days plus topical 2% clindamycin cream applied to penile skin (including under the foreskin if uncircumcised) twice daily for 7 days, as this reduces BV recurrence in female partners from 63% to 35% within 12 weeks. 1

Evidence Supporting Partner Treatment

The most recent high-quality evidence fundamentally contradicts older guidelines:

• A 2025 randomized controlled trial (StepUp trial) demonstrated that treating male partners with combination therapy reduced BV recurrence by 28 percentage points (absolute risk difference of -2.6 recurrences per person-year, P<0.001). 1

• This trial was stopped early by the data and 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 (control group) to 1.6 per person-year (partner-treatment group). 1

Treatment Protocol for Male Partners

Specific regimen:

• Oral metronidazole 400 mg twice daily for 7 days 1
• AND 2% clindamycin cream applied topically to the glans penis and upper shaft (under the foreskin if uncircumcised) twice daily for 7 days 1

Critical patient instructions:

• Avoid all alcohol during metronidazole treatment and for 24 hours after completion to prevent disulfiram-like reactions 2, 3
• Refrain from unprotected intercourse for at least 14 days to allow treatment to take effect 2, 3

Reconciling Contradictory Guidelines

There is a stark contrast between older and newer evidence:

Older guidelines (1993 CDC) stated that treatment of male partners "has not been found beneficial in preventing the recurrence of BV" and is therefore not recommended. 4

However, newer research (2021-2025) provides compelling evidence that:

• Male partners carry BV-associated bacteria on penile skin and in the urethra 5
• Concurrent partner treatment significantly reduces BV-associated bacteria at all three anatomical sites (vagina, penile skin, male urethra) 5
• Women whose male partners adhered to treatment were less likely to experience treatment failure 6
• The 2025 StepUp trial definitively showed clinical benefit with a number needed to treat of approximately 4 to prevent one recurrence 1

Adverse Effects in Male Partners

Men receiving combination therapy may experience:

• Mild gastrointestinal upset 2
• Nausea 1
• Headache 1
• Metallic taste 1

These side effects are generally well-tolerated, with high adherence rates demonstrated in clinical trials. 5, 1

When to Treat Male Partners

Treat male partners when:

• The female partner has recurrent BV (defined as BV recurrence within 12 months of previous treatment) 3, 1
• The couple is in a monogamous relationship 1
• The goal is to prevent recurrence rather than just treat the initial episode 1

No routine follow-up is needed for asymptomatic male partners. 2, 3

Clinical Pitfalls to Avoid

• Do not rely solely on older guidelines that recommend against partner treatment—this recommendation predates modern microbiological evidence showing male carriage of BV-associated organisms 4, 5
• Do not use oral metronidazole alone for male partners—the combination of oral and topical therapy is essential for targeting both urethral and penile skin reservoirs 1
• Do not forget the alcohol warning—disulfiram-like reactions with metronidazole can be severe 2, 3