Antibiotics for bacterial vaginosis

Examples

These antibiotic medications can be taken by mouth in pill form (orally) or inserted into the vagina in cream, gel, or suppository form (ovules). Vaginal creams and gels are used with an applicator that inserts the correct amount of medication. (Tinidazole is only taken by mouth.)

Oral or vaginal metronidazole for 7 days is the first-choice medication for treating bacterial vaginosis.^{1, 2}

How It Works

Metronidazole, clindamycin, and tinidazole are antibiotics that destroy some of the bacteria that cause symptoms of bacterial vaginosis. However, clindamycin also targets the Lactobacillus organisms that normally thrive in a healthy vaginal environment.¹

Why It Is Used

Oral medication

Some women prefer oral medication rather than vaginal administration.

Especially for pregnant women who are high-risk for preterm labor, only oral medications are used to treat bacterial vaginosis. Some doctors recommend that all pregnant women avoid vaginal treatment.

Vaginal medication

Vaginal medications are less likely than the oral forms to cause systemic side effects, such as nausea and vomiting.

How Well It Works

Women who aren't pregnant

For bacterial vaginosis treatment, the Centers for Disease Control and Prevention (CDC) recommends oral metronidazole or vaginal metronidazole gel for 7 days, as they are equally effective.² Metronidazole offers average cure rates of 80% to 90%. Metronidazole is also thought to be most effective for treating infection that has spread into the upper reproductive tract. However, bacterial vaginosis recurrence is common:¹

• 4 weeks after oral metronidazole treatment, 20% of women have recurring bacterial vaginosis.
• 4 weeks after vaginal metronidazole gel treatment, 34% of women have recurring bacterial vaginosis.

The CDC also recommends clindamycin cream 2% for 7 days, while noting that it isn't as effective as metronidazole.² Clindamycin's relapse rate is higher, too: 4 weeks after clindamycin treatment, 56% of women have recurring bacterial vaginosis.¹ Clindamycin ovules are similarly effective.²

Women who are pregnant

For bacterial vaginosis during pregnancy, the CDC recommends oral metronidazole or oral clindamycin for 7 days.² Some experts recommend clindamycin as a second choice because it may be less effective, and it kills the lactobacillus bacteria necessary for preventing ongoing infection.¹

Side Effects

Vaginal medications

Side effects of vaginal clindamycin and metronidazole are generally minor. The most common is a vaginal yeast infection during or after treatment. Clindamycin in particular targets friendly lactobacillus bacteria.¹

The mineral oil in clindamycin cream or ovules can cause latex condoms or diaphragms to fail. This is also true for metronidazole cream and tablets (the gel is fine for use with condoms and diaphragms). Don't trust barrier methods of birth control when using this type of vaginal medication.

Oral medications

Oral treatment can cause:

• Unpleasant metallic taste in the mouth (common only with metronidazole).
• Nausea.
• Vomiting.
• Diarrhea.

Completely avoid alcohol use (including alcohol-based nonprescription medications, such as NyQuil) while taking metronidazole—combining the two may cause severe nausea and vomiting.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

During pregnancy

The Centers for Disease Control recommends treatment for bacterial vaginosis at any time during pregnancy.²

Both oral metronidazole and clindamycin are used for treatment in the second and third trimester of pregnancy. Both medications are unlikely to cause any harm to the fetus.^{2, 3}

• Metronidazole has been well studied and is generally thought to be safe to use during pregnancy.
• Use of clindamycin vaginal cream is not recommended for bacterial vaginosis treatment in pregnant women. The cream form of clindamycin has been shown to have a slightly increased risk for preterm birth.³

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