Treatment of Bacterial Vaginosis
For symptomatic bacterial vaginosis, treat with oral metronidazole 500 mg twice daily for 7 days, which achieves a 95% cure rate and remains the gold standard first-line therapy. 1, 2
First-Line Treatment Options
Oral metronidazole 500 mg twice daily for 7 days is the recommended regimen with the highest cure rate (95%) and should be your default choice for most patients. 3, 1 This systemic approach ensures treatment of potential subclinical upper tract involvement and has the most robust evidence base. 3
Alternative First-Line Regimens (When Oral Route Preferred but Different Dosing Needed)
- Metronidazole 2g single oral dose: Lower efficacy at 84% cure rate, but useful when adherence is a major concern. 3, 1 The convenience may outweigh the slightly reduced efficacy in specific situations.
Topical Alternatives (When Systemic Side Effects Are Problematic)
Metronidazole gel 0.75%: One full applicator (5g) intravaginally twice daily for 5 days achieves similar efficacy to oral therapy with significantly fewer systemic side effects. 3, 1, 4 Peak serum concentrations are less than 2% of standard oral doses. 3
Clindamycin cream 2%: One full applicator (5g) intravaginally at bedtime for 7 days is equally effective. 3, 1 Bioavailability is approximately 4%. 3
Clindamycin 300 mg orally twice daily for 7 days: Another systemic alternative when metronidazole is not tolerated. 3, 1
Critical Precautions
Patients taking metronidazole must avoid all alcohol during treatment and for 24 hours after completion to prevent disulfiram-like reactions (severe nausea, vomiting, flushing). 1, 2 This is non-negotiable.
Clindamycin cream is oil-based and weakens latex condoms and diaphragms for at least 5 days after use—counsel patients accordingly. 1
Cross-allergy warning: Patients with true allergy to oral metronidazole should NOT receive metronidazole gel vaginally. 3, 1 Use clindamycin cream instead. 3, 1
Special Population: Pregnancy
First Trimester
Use clindamycin vaginal cream 2%, one full applicator at bedtime for 7 days. 3, 1 Metronidazole was historically contraindicated in the first trimester, and topical clindamycin minimizes fetal medication exposure. 3
Second and Third Trimesters
Metronidazole 250 mg orally three times daily for 7 days is the preferred regimen, particularly for high-risk pregnant women (those with prior preterm birth). 1, 5 This systemic approach addresses potential subclinical upper tract infection that may contribute to adverse pregnancy outcomes. 5
Alternative acceptable regimens include:
- Metronidazole 2g single oral dose 1
- Clindamycin 300 mg orally twice daily for 7 days 1
- Metronidazole gel or clindamycin cream (though systemic therapy preferred) 3
Rationale for treatment in pregnancy: BV is associated with premature rupture of membranes, preterm labor, and preterm delivery. 3, 1 Treatment in high-risk pregnant women may reduce preterm delivery risk. 1
Follow-Up and Recurrence
No follow-up visit is necessary if symptoms resolve. 3, 1, 2 Only symptomatic patients require treatment. 3
Recurrence is common (50-80% within one year), and you can use any of the alternative treatment regimens for recurrent disease. 2, 6, 7 For true recurrent BV, consider extended metronidazole 500 mg twice daily for 10-14 days, or metronidazole gel 0.75% for 10 days followed by twice weekly maintenance for 3-6 months. 7
Partner Management
Do NOT routinely treat male sex partners. 3, 1, 2 Clinical trials consistently show that partner treatment does not influence the woman's response to therapy, cure rates, or recurrence rates. 3, 1, 2
Additional FDA-Approved Option
Tinidazole is FDA-approved for BV with two regimens: 2g once daily for 2 days or 1g once daily for 5 days, achieving therapeutic cure rates of 22-32% above placebo. 8 However, this agent has less clinical experience than metronidazole and is not included in CDC guidelines as first-line therapy. 2
Clinical Context for Treatment
Only treat symptomatic BV—asymptomatic colonization does not require therapy unless the patient is undergoing invasive procedures (surgical abortion, hysterectomy, IUD placement, endometrial biopsy) where BV increases risk of postoperative infectious complications including endometritis and PID. 3, 1