Treatment of Bacterial Vaginosis
The preferred first-line treatment for bacterial vaginosis is oral metronidazole 500 mg twice daily for 7 days, which achieves a 95% cure rate and is recommended by the CDC as the most efficacious regimen. 1, 2
First-Line Treatment Options
You have three equally acceptable first-line regimens to choose from:
Oral metronidazole 500 mg twice daily for 7 days - This is the preferred option with the highest efficacy (95% cure rate) and should be your default choice 1, 2
Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days - Equally effective as oral therapy but produces fewer systemic side effects, making it preferable for patients who experience gastrointestinal upset with oral metronidazole 1, 2
Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days - Another effective first-line option, particularly useful for patients with metronidazole allergy or intolerance 1, 2
Critical Patient Counseling
Patients taking metronidazole must avoid all alcohol during treatment and for 24 hours after completion to prevent a disulfiram-like reaction. 1, 2 This is non-negotiable and should be emphasized strongly.
Clindamycin cream and ovules are oil-based and will weaken latex condoms and diaphragms, so patients must use alternative contraception during treatment. 1, 2
Alternative Regimens (Lower Efficacy)
When compliance is a major concern, consider:
Metronidazole 2g orally as a single dose - This has a lower cure rate (84% vs 95%) and should only be used when the 7-day regimen is not feasible 1, 2
Oral clindamycin 300 mg twice daily for 7 days - Reserve this for patients who cannot use metronidazole 1, 2
Tinidazole 2g once daily for 2 days OR 1g once daily for 5 days - FDA-approved alternative with therapeutic cure rates of 27.4% and 36.8% respectively (though these rates appear lower due to more stringent cure criteria requiring resolution of all 4 Amsel's criteria plus Nugent score <4) 3
Special Populations
Pregnancy
All symptomatic pregnant women should be tested and treated for BV. 1
First trimester: Use clindamycin vaginal cream, as metronidazole is contraindicated 1
Second and third trimesters: Metronidazole 250 mg orally three times daily for 7 days is the recommended regimen 1, 2
High-risk pregnant women (history of preterm delivery): Treatment may reduce risk of prematurity, making treatment particularly important in this population 1
Breastfeeding Women
Standard CDC guidelines apply, as metronidazole is compatible with breastfeeding despite small amounts being excreted in breast milk. 1
HIV-Infected Patients
Treat identically to HIV-negative patients using the same regimens. 1
Patients with Metronidazole Allergy
Use clindamycin cream or oral clindamycin as the preferred alternative. 1 Never administer metronidazole vaginally to patients with oral metronidazole allergy. 1
Follow-Up and Partner Management
Do not routinely treat male sex partners - This has not been shown to influence cure rates or reduce recurrence 1, 2
Special Clinical Situations
Screen and treat all women with BV before surgical abortion or hysterectomy, as BV increases risk of postoperative infectious complications. 2 Treatment with metronidazole reduces post-abortion pelvic inflammatory disease by 10-75%. 2
Recurrent BV Management
If BV recurs (which happens in 50% of women within 1 year), use metronidazole 500 mg twice daily for 10-14 days; if this fails, switch to metronidazole vaginal gel 0.75% for 10 days, followed by twice weekly application for 3-6 months. 4