What is the recommended treatment for bacterial vaginosis, including first‑line and alternative options?

Treatment of Bacterial Vaginosis

For symptomatic bacterial vaginosis in non-pregnant women, treat with metronidazole 500 mg orally twice daily for 7 days, which achieves cure rates of 78-84% and is the CDC-recommended first-line therapy. 1

First-Line Treatment Options

All three of the following regimens are considered equally effective first-line options by the CDC: 1, 2

• Metronidazole 500 mg orally twice daily for 7 days – This is the most commonly recommended regimen with cure rates of 78-84% 1
• Metronidazole gel 0.75%, one full applicator (5g) intravaginally twice daily for 5 days – Achieves comparable cure rates of 78-84% with minimal systemic absorption (less than 2% of oral dosing) 1, 3
• Clindamycin 2% vaginal cream, one full applicator (5g) intravaginally at bedtime for 7 days – Also achieves 78-84% cure rates 1, 2

Alternative Regimens (Lower Efficacy)

Use these only when first-line options are not feasible: 1

• Metronidazole 2g orally as a single dose – This has significantly lower efficacy than the 7-day regimen and should NOT be used as first-line therapy 1, 4
• Clindamycin 300 mg orally twice daily for 7 days – Lower efficacy than first-line options 1

Critical Patient Instructions

Alcohol Avoidance

• Patients taking metronidazole (oral or vaginal) must avoid ALL alcohol during treatment and for 24 hours after completion to prevent disulfiram-like reactions (flushing, nausea, vomiting, tachycardia) 1, 2, 5

Contraception Warning

• Clindamycin cream is oil-based and weakens latex condoms and diaphragms for the entire 7-day treatment course, making barrier contraception unreliable 1, 2

Treatment Completion

• Patients must complete the full treatment course even if symptoms resolve early 1

Treatment of Sexual Partners

Do NOT routinely treat male sexual partners. Multiple randomized controlled trials demonstrate that partner treatment does not alter the woman's clinical response, relapse rate, or recurrence rate. 1, 2, 5

Follow-Up

• No routine follow-up visits are necessary if symptoms resolve 1, 2
• Patients should return only if symptoms persist or recur 1, 5
• Recurrence is common (50-80% within 1 year), and any of the alternative regimens may be used for recurrent disease 1, 2

Special Populations

Pregnant Women

All symptomatic pregnant women should be treated because BV is associated with premature rupture of membranes, preterm labor, preterm birth, and postpartum endometritis. 3, 2

• Recommended regimen: Metronidazole 500 mg orally twice daily for 7 days 2
• High-risk pregnant women (history of preterm delivery) with asymptomatic BV may benefit from screening and treatment in the early second trimester 3, 2
• Follow-up evaluation one month after treatment completion is recommended for pregnant women to verify cure due to risk of adverse pregnancy outcomes 3, 1, 5
• Lower doses are used in pregnancy to minimize fetal exposure 3
• Clindamycin vaginal cream should NOT be used in pregnancy due to increased preterm deliveries in randomized trials 3

Before Surgical Procedures

• Screen and treat asymptomatic women before surgical abortion or hysterectomy – Treatment with metronidazole substantially reduces post-abortion pelvic inflammatory disease by 10-75% 2

HIV-Infected Patients

• Patients with BV who are HIV-positive should receive the same treatment regimen as HIV-negative patients 3

Common Pitfalls to Avoid

• Do NOT culture for Gardnerella vaginalis – This organism can be isolated from 50% of normal women and is not specific for BV 1
• Do NOT treat asymptomatic women unless they are high-risk pregnant women or undergoing surgical abortion procedures 1, 2
• Do NOT use single-dose metronidazole as first-line treatment due to significantly lower efficacy 1
• Do NOT use clindamycin vaginal cream in pregnancy due to association with preterm delivery 3

Diagnosis Confirmation

Before treating, confirm diagnosis using Amsel's criteria (at least 3 of 4 required): 2, 6

• Homogeneous, white, non-inflammatory vaginal discharge
• Vaginal pH greater than 4.5
• Positive whiff test (fishy odor with 10% KOH)
• Clue cells on microscopic examination

Alternative: Gram stain with Nugent score ≥4 2, 7