Bacterial Vaginosis: Facts and Myths

JUNE 01, 2008
Jeffrey A. Kyle, PharmD, and Allison Butcher, PharmD

Drs. Kyle and Butcher are both assistant professors of pharmacy practice at the Gregory School of Pharmacy at Palm Beach Atlantic University,West Palm Beach, Florida.

Bacterial vaginosis (BV), trichomoniasis, and candidiasis are the 3 most frequent infections associated with vaginal discharge. Among sexually active women in the United States, BV is the most prevalent vaginal discharge infection.1

BV results from an imbalance between normal hydrogen peroxide?producing Lactobacillus sp and overgrowth of multiple pathogens in the vagina.1,2 The exact etiology of this imbalance is not fully known. Pathogens most commonly isolated include Gardnerella vaginalis, Mycoplasma hominis, Bacteroides sp (other than Bacteroides fragilis), Ureaplasma urealyticum, Prevotella sp, and Mobiluncus sp. Although a majority of women with BV remain asymptomatic, some may experience bothersome symptoms, such as vaginal discharge, malodor, and rarely vaginal pain, itching, and burning.2

Common Myths

BV is not considered a sexually transmitted disease (STD), but it appears to be related to sexual activity because those who are not sexually active are rarely affected.1 Other risk factors that may lead to disruption of normal vaginal flora and increase the chances of developing BV include multiple or new sex partners, frequent vaginal douching, use of an intrauterine contraceptive device, and lack of vaginal lactobacilli.1 Toilet seats, bedding, and swimming pools are not risk factors for the development of BV.2


BV should be treated in all patients who are symptomatic and in asymptomatic pregnant patients at risk for preterm delivery.1 The benefits of treating BV are relief from vaginal symptoms and signs of infection, reduction in the risk for infectious complications following surgical abortion or hysterectomy, and possibly a reduction in the risk for other infections (eg, HIV and STDs).1

The regimens currently recommended by the Centers for Disease Control and Prevention (CDC) include either oral or intravaginal preparations of metronidazole or clindamycin (Table). Both medications have shown to achieve cure rates of >90% when taken as recommended.1 Treatment of male sexual partners is not recommended and is usually unnecessary, as the organisms responsible for generating BV symptomology do not persist in the male urethra.

As a reminder, alcohol should be avoided in all patients using metronidazole (both oral and intravaginal) for the duration of treatment and for 24 hours after the last dose. The combination of metronidazole and alcohol in any form may lead to a disulfiram-like reaction with symptoms of flushing, nausea, vomiting, thirst, palpitations, chest pain, vertigo, and hypotension.

Clindamycin cream is an oil-based preparation, so patients should be counseled that it could weaken latex condoms and diaphragms for up to 5 days after use. Clindamycin also should be avoided during the second half of pregnancy due to risk for low birth weight infants and neonatal infections. Metronidazole use during pregnancy has not been associated with teratogenic or mutagenic effects in newborns.

Although not reflected in the current CDC recommendations, tinidazole, an oral antiprotozoal drug available since 2004, recently has been approved for treatment of bacterial vaginosis.3 Tinidazole's spectrum of activity against BV, adverse side-effect profile, and drug interactions seem to be similar to that of metronidazole.3,4 The recommended dose of tinidazole for BV is 2 g once daily for 2 days or 1 g once daily for 5 days, and it is available in 250- and 500-mg tablets. Currently, studies are underway directly comparing the efficacy of tinidazole and metronidazole in treating BV to assist clinicians in establishing tinidazole's role.

Alternatives to antibiotics also are being investigated. Preliminary evidence shows Lactobacillus acidophilus intravaginal suppositories to be of benefit in the treatment of BV, as well as the oral consumption of Lactobacillus-enriched yogurt. Yogurt intravaginal suppositories should not be recommended as the Lactobacillus found in yogurt is not the same as that found in normal vaginal flora. Another treatment under investigation is the use of tea tree oil; however, this should not be recommended until further data are available.

Recurrence of bacterial vaginosis symptoms is fairly common due to continued infection by BV-associated organisms and/or the continued deficiency of Lactobacillus sp in the vagina.1 Women should be advised to follow up with their physician and return for additional treatment if symptoms do not resolve. Recurrent infections can be managed either with the original regimen or an alternative regimen; however, a specialist should be consulted for women with multiple recurrences.2

Patient Education

Patient counseling and education regarding BV should include an explanation of the disease, treatment options, and risk reduction. Inform patients to report malodorous, especially fishy smelling, vaginal discharge. Remind patients that although BV is not sexually transmitted, an increased risk of infection exists in patients with new or multiple sexual partners. To decrease the risk of developing BV, remind patients to avoid douching and limit the number of sexual partners.

Treatment Regimens for Bacterial Vaginosis


Metronidazole tablets

500 mg orally bid for 7 days

Metronidazole gel 0.75%

One full applicator (5 g) intravaginally qd for 5 days

Clindamycin cream 2%

One full applicator (5 g) intravaginally at bedtime for 7 days


Clindamycin capsules

300 mg orally bid for 7 days

Clindamycin ovules

100 mg intravaginally at bedtime for 3 days

Recommended for Pregnant Women

Metronidazole tablets

500 mg orally bid for 7 days

Metronidazole tablets

250 mg orally tid for 7 days

Clindamycin capsules

300 mg orally bid for 7 days

Adapted from references 1 and 2.


  1. Centers for Disease Control and Prevention. Sexually transmitted disease treatment guidelines. MMWR. 2006;55:49-52.
  2. Bacterial vaginosis. Center for Disease Control and Prevention Web site. Accessed February 7, 2008.
  3. Tinidazole (Tindamax)-a new antiprotozoal drug. Med Lett Drugs Ther. 2004;46:70-72.
  4. Austin MN, Meyn LA, Hillier SL. Susceptibility of vaginal bacteria to metronidazole and tinidazole. Anaerobe. 2006;12:227-230.