Keflex (Cephalexin) is NOT Effective for Bacterial Vaginosis Treatment
Keflex (cephalexin) is not recommended for bacterial vaginosis treatment as it is not included in any treatment guidelines for BV. According to CDC guidelines, the recommended first-line treatments for bacterial vaginosis are metronidazole and clindamycin 1, 2.
Recommended Treatment Options for Bacterial Vaginosis
First-Line Treatments
- Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) 2
- Metronidazole gel 0.75% intravaginally once daily for 5 days (95% cure rate) 2
- Clindamycin cream 2% intravaginally at bedtime for 7 days 1
Alternative Regimens
- Metronidazole 2g orally in a single dose (84% cure rate) 1, 2
- Clindamycin 300 mg orally twice daily for 7 days 1
Why Keflex Is Not Appropriate for BV
Bacterial vaginosis involves a complex shift in vaginal flora with overgrowth of anaerobic bacteria including Gardnerella vaginalis, Prevotella species, and Mobiluncus species. Keflex (cephalexin) is a first-generation cephalosporin that:
- Has poor activity against the anaerobic bacteria that cause BV
- Is not included in any treatment guidelines for BV 1, 2
- Would not address the underlying microbial imbalance characteristic of BV
Diagnostic Considerations
Proper diagnosis of BV is essential before initiating treatment. BV is diagnosed using Amsel's criteria, which requires the presence of at least 3 of 4 criteria:
- Homogeneous, white discharge adhering to vaginal walls
- Presence of clue cells on microscopic examination
- Vaginal fluid pH greater than 4.5
- Fishy odor of vaginal discharge before or after addition of 10% KOH (whiff test) 2
Treatment Efficacy Considerations
Recent research has demonstrated that:
- Oral and vaginal metronidazole have similar efficacy (89.9% vs. 92.5% cure rates), but the vaginal route has significantly fewer side effects 3
- Dequalinium chloride, a broad-spectrum antiseptic, has been shown to be non-inferior to oral metronidazole with better tolerability in a 2024 study 4
- Treatment failure rates can be as high as 38.7%, requiring repeat treatment 5
- Recurrence rates can be as high as 50% within one year of treatment 6
Special Considerations
Pregnancy
For pregnant women, the CDC recommends:
- First trimester: clindamycin cream
- Second and third trimesters: metronidazole (oral or gel) or clindamycin cream 2
Side Effects and Precautions
- Patients using metronidazole should avoid alcohol during treatment and for 24 hours afterward 1
- Clindamycin cream is oil-based and may weaken latex condoms and diaphragms 1
- Intravaginal metronidazole causes significantly fewer side effects (nausea: 10.2% vs. 30.4%; abdominal pain: 16.8% vs. 31.9%) compared to oral administration 3
Management of Sexual Partners
Routine treatment of sexual partners is not recommended for BV according to CDC guidelines 1, 2. However, consistent condom use may help prevent recurrence 2.
Follow-Up
Follow-up visits are generally unnecessary if symptoms resolve. However, for pregnant women, a follow-up evaluation one month after treatment completion is recommended 1, 2.