Treatment of Bacterial Vaginosis
For a patient positive for bacterial vaginosis, treat with oral metronidazole 500 mg twice daily for 7 days, which achieves a 95% cure rate and is the most effective first-line therapy. 1
First-Line Treatment Options
Oral metronidazole 500 mg twice daily for 7 days is the preferred regimen due to its superior efficacy compared to all other options. 2, 1 This regimen consistently demonstrates the highest cure rates and should be your default choice for initial treatment. 1
Equally Effective Alternatives (When Oral Therapy Not Preferred)
If the patient prefers intravaginal therapy or cannot tolerate systemic medication:
Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days provides equivalent efficacy to oral therapy with fewer systemic side effects (peak serum concentrations <2% of oral dosing). 2, 1
Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days is another first-line option, though it appears slightly less efficacious than metronidazole regimens. 2, 1, 3
Alternative Regimens (Lower Efficacy)
Use these only when compliance is a major concern or first-line options have failed:
Metronidazole 2g orally as a single dose has lower efficacy (84% cure rate vs. 95% for 7-day regimen) but may be appropriate when adherence is questionable. 2, 1
Oral clindamycin 300 mg twice daily for 7 days is reserved for metronidazole allergy or intolerance. 2, 1
Clindamycin ovules 100g intravaginally once at bedtime for 3 days is another alternative option. 2
Critical Patient Counseling
Patients taking metronidazole must avoid all alcohol during treatment and for 24 hours afterward due to disulfiram-like reactions. 2, 4, 1 This is non-negotiable and must be emphasized.
Warn patients using clindamycin cream or ovules that these oil-based products weaken latex condoms and diaphragms, requiring alternative contraception during treatment. 2, 1
Special Populations
Pregnancy
All symptomatic pregnant women must be tested and treated due to associations with preterm rupture of membranes, chorioamnionitis, and preterm labor. 2, 1
First trimester: Use clindamycin vaginal cream 2% (one applicator at bedtime for 7 days) as metronidazole is contraindicated. 2, 1
Second and third trimesters: Use metronidazole 250 mg orally three times daily for 7 days (note the different dosing from non-pregnant patients). 4, 1
High-risk pregnant women (history of preterm delivery) should have follow-up evaluation at 1 month after treatment completion. 4
HIV-Positive Patients
Treat HIV-positive patients identically to HIV-negative patients using the same regimens and dosing. 2, 1
Metronidazole Allergy or Intolerance
Use clindamycin cream or oral clindamycin as the preferred alternative. 2, 1
Never give metronidazole gel to patients with true metronidazole allergy, even though it's topical—systemic absorption still occurs. 2, 1
Recurrent Bacterial Vaginosis
If symptoms recur (which happens in approximately 50-60% of patients within one year): 5, 6
Treat with metronidazole 500 mg orally twice daily for 10-14 days (extended course), followed by suppressive therapy with metronidazole gel 0.75% twice weekly for 3-6 months. 4 This suppressive regimen reduces recurrence rates from approximately 60% to 25%. 4
Management of Sexual Partners
Do not routinely treat sexual partners. 2, 4, 1 Multiple randomized controlled trials consistently demonstrate that partner treatment does not influence the woman's response to therapy, relapse rates, or recurrence rates. 2, 1 This is a common pitfall—resist pressure to treat partners as it provides no benefit.
Follow-Up
Follow-up visits are unnecessary if symptoms resolve. 2, 1 Simply advise patients to return if symptoms recur, at which point you can use an alternative treatment regimen or the extended/suppressive approach for recurrent disease. 2, 1
Preoperative Screening
Before surgical abortion or hysterectomy, screen and treat women with BV (even if asymptomatic) in addition to routine prophylaxis. 2, 1 Treatment with metronidazole substantially reduces post-abortion pelvic inflammatory disease by 10-75%. 2, 1 Evidence for screening before other invasive procedures (IUD placement, hysterosalpingography, cesarean section, uterine curettage) is insufficient to make routine recommendations. 2