What is the dose of metronidazole (metro) gel for treating bacterial vaginosis or rosacea?

Metronidazole Gel Dosing

For bacterial vaginosis, use metronidazole gel 0.75% one full applicator (5 grams) intravaginally once daily at bedtime for 5 days, which is equally effective as twice-daily dosing and is the FDA-approved regimen. 1

Recommended Dosing Regimens

For Bacterial Vaginosis (Primary Indication)

Standard FDA-approved dosing:

• Metronidazole gel 0.75%: one full applicator (5 grams, containing 37.5 mg metronidazole) intravaginally once daily at bedtime for 5 days 1
• Alternative: twice daily for 5 days (older regimen, no longer preferred) 2

Clinical equivalence data:

• Once-daily dosing achieves 77% cure rate at 7-12 days and 58% at 28-35 days 3
• Twice-daily dosing achieves 80% cure rate at 7-12 days and 61% at 28-35 days 3
• These differences are not statistically significant, confirming once-daily dosing is equally effective 3

For Rosacea

Metronidazole gel is used topically for rosacea, but this is a different formulation and concentration (typically 0.75% or 1% applied to facial skin once or twice daily). This is not the same product as intravaginal metronidazole gel for bacterial vaginosis.

Comparison with Oral Metronidazole

When to choose vaginal gel over oral:

• Patient cannot tolerate systemic side effects (nausea occurs in 10% with gel vs. 30% with oral; abdominal pain in 17% vs. 32%; metallic taste in 9% vs. 18%) 4
• Patient prefers to avoid oral medication 4
• Intolerance (but not true allergy) to oral metronidazole 2, 5

When to choose oral metronidazole instead:

• Pregnant women at high risk for preterm delivery (history of prior preterm birth) require systemic therapy 2, 5
• Need for maximum adherence with single-dose therapy (though this has lower efficacy at 84%) 2

Efficacy comparison:

• Oral metronidazole 500 mg twice daily for 7 days: 84% cure rate 2
• Metronidazole gel 0.75% for 5 days: 75% cure rate 2
• These differences are not clinically significant (cure rates 7-10 days post-treatment: 84% oral vs. 75% gel) 2

Critical Patient Counseling Points

Alcohol avoidance:

• Patients must avoid alcohol during treatment and for 24 hours after completion, even with vaginal gel formulation 2, 6
• This applies despite systemic absorption being <2% of oral doses 2

Allergy considerations:

• Patients with true allergy to oral metronidazole should NOT receive metronidazole gel vaginally 2, 5
• Use clindamycin cream 2% as alternative in allergic patients 2

Condom compatibility:

• Metronidazole gel does not weaken latex condoms (unlike clindamycin cream which is oil-based) 6, 5

Resuming Sexual Activity

• No mandatory waiting period after completing treatment 6
• Resume sexual activity once symptoms resolve 6
• Partner treatment is NOT recommended (does not affect cure rates or recurrence) 2, 6, 5

Follow-up and Recurrence

Follow-up:

• Unnecessary if symptoms resolve 2, 6
• Consider 1-month follow-up only in high-risk pregnant women 2

Recurrence management:

• Recurrence occurs in approximately 50% of women within 1 year 7
• For recurrent BV: metronidazole 500 mg orally twice daily for 10-14 days, then consider metronidazole gel 0.75% twice weekly for 3-6 months as suppressive therapy 7
• Recurrence rates after initial cure are similar whether treated with oral or vaginal metronidazole (approximately 70% recur within 6 months) 8

Common Pitfalls to Avoid

• Do not use twice-daily vaginal dosing when once-daily is equally effective and improves adherence 1, 3
• Do not treat male partners routinely (no benefit demonstrated) 2, 5
• Do not confuse intravaginal metronidazole gel for BV with topical metronidazole gel for rosacea (different products and indications)
• Do not give metronidazole gel to patients with true metronidazole allergy 2, 5