Examples

These antibiotic medicines 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 medicine. (Tinidazole is only taken by mouth.)

Oral or vaginal metronidazole for 7 days is the first-choice medicine 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.

Why It Is Used

Oral medicine

Some women prefer oral medicine rather than vaginal administration.

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

Vaginal medicine

Vaginal medicines 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 for 7 days or vaginal metronidazole gel for 5 days, as they are equally effective. ² Metronidazole offers average cure rates of 80% to 90%. Also, metronidazole is thought to be most effective for treating infection that has spread into the upper reproductive tract. But bacterial vaginosis recurrence is common. If the infection has been treated successfully, some doctors may prescribe metronidazole gel twice weekly for a few months. This keeps the infection from coming back.

The CDC also recommends clindamycin cream 2% for 7 days, while noting that it might not be as effective as metronidazole. ² Clindamycin's relapse rate is higher: 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. ¹

Side Effects

Vaginal medicines

Side effects of vaginal clindamycin and metronidazole are generally minor. The most common is a vaginal yeast infection during or after treatment.

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 medicine.

Oral medicines

Oral treatment can cause:

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

Completely avoid alcohol use (including alcohol-based nonprescription medicines, such as NyQuil) while you are taking metronidazole or tinidazole, because combining alcohol with these medicines 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

Either oral metronidazole or oral clindamycin are used for treatment in the second and third trimester of pregnancy. Neither medicine is likely to cause any harm to the fetus. ^{2, 3} Tinidazole is not recommended for use during pregnancy.

• 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
• Tinidazole is not recommended for use during pregnancy.

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