Metronidazole Vaginal Gel Dosing for Bacterial Vaginosis
The standard dosing for metronidazole vaginal gel 0.75% is one full applicator (5 grams containing 37.5 mg metronidazole) intravaginally once daily at bedtime for 5 days. 1
FDA-Approved Dosing Regimens
The FDA approves two dosing options for metronidazole vaginal gel 0.75%: 1
- Once-daily dosing: One full applicator (5 grams) intravaginally at bedtime for 5 days
- Twice-daily dosing: One full applicator (5 grams) intravaginally twice daily for 5 days
Clinical Equivalence and Preferred Regimen
Once-daily dosing is equally effective as twice-daily dosing and should be preferred for improved compliance. 2, 3
- Clinical cure rates at 1 month are equivalent: 57-58% for once-daily versus 61-62% for twice-daily dosing 2, 3
- Early cure rates (7-12 days post-treatment) are also comparable: 77% for once-daily versus 80% for twice-daily 2
- Side effects are mild and equivalent between regimens, with no treatment discontinuations 2
Comparison to Oral Therapy
Metronidazole vaginal gel achieves similar efficacy to oral metronidazole but with significantly fewer systemic side effects: 4
- Cure rates are equivalent: 71% for vaginal gel versus 71% for oral metronidazole at final visit 4
- Gastrointestinal complaints occur in only 33% of vaginal gel users versus 52% of oral metronidazole users 4
- Mean peak serum concentrations with vaginal gel are less than 2% of standard 500 mg oral doses 5
Critical Patient Counseling
Patients must avoid all alcohol consumption during treatment and for 24 hours after completion to prevent disulfiram-like reactions. 5, 6, 7
When NOT to Use Vaginal Gel
Do not use metronidazole vaginal gel for trichomoniasis—it has less than 50% efficacy for this indication and oral therapy is required. 5
Patients with true metronidazole allergy should not receive vaginal gel; use clindamycin cream 2% instead. 6, 7
Special Population: Pregnancy
Metronidazole is contraindicated in the first trimester of pregnancy. 5, 6, 7
After the first trimester, oral metronidazole 250 mg three times daily for 7 days is preferred over vaginal gel for pregnant women. 5, 6, 7
Partner Management
Routine treatment of male sex partners is NOT recommended, as clinical trials demonstrate that partner treatment does not affect cure rates or reduce recurrence. 6, 7