What is the treatment for bacterial vaginosis?

Treatment of Bacterial Vaginosis

First-Line Treatment Regimens

Oral metronidazole 500 mg twice daily for 7 days is the preferred first-line treatment for bacterial vaginosis, achieving cure rates up to 95%. 1, 2, 3

The following regimens are equally acceptable first-line options for non-pregnant women:

• Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days—equally efficacious as oral therapy but with fewer systemic side effects (less than 2% of serum levels achieved with oral dosing) 4, 1

• Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days 4, 1

Critical Patient Counseling

• Patients must avoid all alcohol during metronidazole treatment and for 24 hours after completion to prevent disulfiram-like reactions (flushing, nausea, vomiting, tachycardia) 4, 1, 3

• Clindamycin cream and ovules are oil-based and will weaken latex condoms and diaphragms—patients must use alternative contraception during treatment 4, 1, 3

Alternative Regimens (Lower Efficacy)

Use these only when compliance with 7-day regimens is a major concern:

• Metronidazole 2g orally as a single dose—cure rate only 84% compared to 95% for the 7-day regimen 4, 1, 2

• Oral clindamycin 300 mg twice daily for 7 days 4, 2

• Tinidazole 2g once daily for 2 days OR 1g once daily for 5 days—demonstrated therapeutic cure rates of 22-32% (using strict criteria requiring resolution of all 4 Amsel criteria plus Nugent score <4) 5

Treatment in Pregnancy

High-Risk Pregnant Women (Prior Preterm Birth)

Metronidazole 250 mg orally three times daily for 7 days is the recommended treatment to reduce risk of prematurity and relieve symptoms 1, 2, 3, 6

• Systemic therapy is preferable to treat possible subclinical upper tract infection 6
• Treatment may reduce risk of preterm delivery in this population 4

Low-Risk Pregnant Women (No Prior Preterm Birth)

Treat only if symptomatic with metronidazole 250 mg orally three times daily for 7 days 3, 6

First Trimester Considerations

Clindamycin vaginal cream is preferred during first trimester due to historical concerns about metronidazole teratogenicity, though meta-analyses have not demonstrated teratogenicity in humans 4, 1

Patients with Metronidazole Allergy or Intolerance

Use clindamycin cream 2% intravaginally or oral clindamycin 300 mg twice daily for 7 days 1, 2

• Patients allergic to oral metronidazole should NOT receive metronidazole vaginally 1, 2

Special Clinical Situations

Before Surgical Procedures

Screen and treat all women with BV before surgical abortion or hysterectomy in addition to routine prophylaxis 4, 3

• Treatment with metronidazole reduces postabortion PID by 10-75% 4, 3
• BV increases risk of postoperative infectious complications including endometritis, PID, and vaginal cuff cellulitis 4, 3

HIV-Infected Patients

Treat with the same regimens as HIV-negative patients—no modification needed 1

Breastfeeding Women

Standard CDC guidelines apply—metronidazole is compatible with breastfeeding as only small amounts are excreted in breast milk 1

Follow-Up and Recurrence Management

• Follow-up visits are unnecessary if symptoms resolve 4, 1, 2, 3

• For pregnant high-risk women, consider follow-up evaluation at 1 month after treatment completion to confirm therapeutic success 4

• Recurrence occurs in 50-80% of women within one year—patients should be advised to return if symptoms recur 4, 7, 8

• For recurrent BV, use extended metronidazole 500 mg twice daily for 10-14 days; if ineffective, metronidazole gel 0.75% for 10 days followed by twice weekly for 3-6 months 7

Management of Sex Partners

Do NOT routinely treat male sex partners—clinical trials demonstrate no effect on cure rates, relapse, or recurrence 4, 2, 3, 6

Common Pitfalls to Avoid

• Do not use single-dose metronidazole 2g as first-line therapy—it has significantly lower efficacy (84% vs 95%) and should be reserved only for compliance concerns 1, 2

• Do not prescribe shorter courses than recommended—7-day regimens for oral metronidazole and clindamycin are necessary for maximal effectiveness 9

• Do not forget to warn about alcohol with metronidazole—this is a critical safety issue that causes significant patient distress if not addressed 4, 1, 3

• Do not assume vaginal preparations are less effective—metronidazole gel has equivalent efficacy to oral therapy with fewer systemic side effects 4, 1