What is the recommended treatment for bacterial vaginosis?

Bacterial Vaginosis Treatment

The CDC recommends metronidazole 500 mg orally twice daily for 7 days as the first-line treatment for bacterial vaginosis, achieving a 95% cure rate—the highest efficacy among all available regimens. 1

First-Line Treatment Options

You have three equally acceptable first-line regimens to choose from, though oral metronidazole demonstrates superior efficacy:

• Metronidazole 500 mg orally twice daily for 7 days - This achieves a 95% cure rate and is the preferred option 1, 2
• Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days - Equally effective as oral therapy but with significantly fewer systemic side effects (less nausea, abdominal pain, and metallic taste) 1, 2, 3
• Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days - Another effective first-line option 1, 2

Critical Patient Counseling Points

Patients must avoid all alcohol during metronidazole treatment and for 24 hours after completion to prevent disulfiram-like reactions (flushing, nausea, vomiting, tachycardia). 1, 2

Clindamycin cream and ovules are oil-based and will weaken latex condoms and diaphragms for up to 5 days after use. 1, 2

Alternative Regimens (Use Only When Compliance Is Uncertain)

• Metronidazole 2g orally as a single dose - This has only an 84% cure rate compared to 95% for the 7-day regimen, so reserve this for situations where you seriously doubt the patient will complete a full course 1, 2
• Clindamycin 300 mg orally twice daily for 7 days - Use this when metronidazole cannot be tolerated 1, 2
• Tinidazole 2g once daily for 2 days or 1g once daily for 5 days - FDA-approved alternative with therapeutic cure rates of 22-32% (though measured by stricter criteria than older studies) 4

Special Populations

Pregnant Women

All symptomatic pregnant women should be tested and treated for BV. 2

• First trimester: Use clindamycin vaginal cream (metronidazole is contraindicated) 2
• Second and third trimesters: Metronidazole 250 mg orally three times daily for 7 days 1, 2, 5
• High-risk pregnant women (history of preterm delivery): Metronidazole 250 mg orally three times daily for 7 days is preferred because systemic therapy addresses potential subclinical upper tract infection 1, 5
• Low-risk pregnant women: Treat only if symptomatic, using metronidazole 250 mg orally three times daily for 7 days 1, 5

Breastfeeding Women

• Standard CDC guidelines apply—metronidazole is compatible with breastfeeding as only small amounts are excreted in breast milk 2
• Intravaginal preparations minimize systemic absorption (less than 2% of oral dose serum concentrations), making them particularly suitable 2

HIV-Positive Patients

• Treat with the same regimens as HIV-negative patients 2

Patients with Metronidazole Allergy

• Use clindamycin cream or oral clindamycin 2
• Never give metronidazole vaginally to patients allergic to oral metronidazole 2

Management Principles

Do not treat sex partners routinely—clinical trials demonstrate no effect on cure rates, relapse, or recurrence. 1, 2

Follow-up visits are unnecessary if symptoms resolve. 1, 2

When Treatment Is Mandatory (Even If Asymptomatic)

Screen and treat all women with BV before surgical abortion or hysterectomy, as BV increases risk of postoperative infectious complications and treatment with metronidazole reduces post-abortion PID by 10-75%. 1, 2

Common Pitfalls to Avoid

• Do not confuse BV with cytolytic vaginosis (pH <4.0 vs. >4.5 in BV)—cytolytic vaginosis worsens with antibiotics and requires alkalinizing treatment with sodium bicarbonate 6
• Do not use single-dose metronidazole as routine first-line therapy—the 11% lower cure rate matters clinically 1
• Do not forget to warn about alcohol with metronidazole—this is a serious drug interaction 1, 2
• Do not assume condoms are protective during clindamycin cream use—they will be weakened 1, 2