From the Guidelines
Oral vancomycin is now recommended as the first-line treatment for Clostridioides difficile infections (CDI) due to its higher cure rates and lower recurrence rates compared to metronidazole, particularly in severe infections. Metronidazole has traditionally been used to treat mild to moderate CDI, but its use is now limited to cases where vancomycin is contraindicated or unavailable 1. The typical regimen for metronidazole is 500 mg orally three times daily for 10-14 days, but its efficacy is lower compared to vancomycin, especially in severe cases 2. Vancomycin, on the other hand, has been shown to be superior to metronidazole in treating CDI, with a higher cure rate and lower recurrence rate, particularly in severe infections 2. The recommended regimen for vancomycin is 125 mg orally four times daily for 10 days. It is essential to discontinue the inciting antibiotic if possible, avoid antimotility agents, and implement appropriate infection control measures to prevent transmission. Some key points to consider when treating CDI include:
- Discontinuing the inciting antibiotic if possible
- Avoiding antimotility agents
- Implementing appropriate infection control measures to prevent transmission
- Using vancomycin as the first-line treatment for all CDI severities
- Limiting metronidazole use to cases where vancomycin is contraindicated or unavailable. The most recent guidelines recommend vancomycin as the first-line treatment for CDI, and metronidazole should only be used in specific cases where vancomycin is not available or contraindicated 1, 2.
From the FDA Drug Label
Vancomycin hydrochloride capsules are not effective for other types of infections. Orally administered vancomycin hydrochloride capsules are not effective for other types of infections.
The FDA drug label does not answer the question.
From the Research
Reasons for Not Using Oral Vancomycin as 1st Choice
- Oral vancomycin is not always the first choice for treating C. difficile infection (CDI) due to various factors, including disease severity and patient response 3, 4.
- Metronidazole has historically been considered first-line therapy for patients with mild to moderate CDI, although it is inferior to vancomycin for clinical cure 3.
- The choice of therapy may have substantial consequences on downstream outcomes, such as recurrence and mortality, which have been less studied 3.
Comparison of Vancomycin and Metronidazole
- A retrospective, propensity-matched cohort study found that treatment with vancomycin was associated with a lower risk of 30-day mortality compared to metronidazole, particularly in patients with severe CDI 3.
- Another study found that metronidazole is associated with lower rates of treatment success compared to vancomycin and should no longer be used as primary therapy for the first episode of CDI or recurrent disease 4.
- Vancomycin or fidaxomicin are now recommended for first-line therapy for most cases of CDI 4, 5.
Alternative Treatment Options
- Fecal microbiota transplantation (FMT) has emerged as a remarkably successful treatment for recurrent CDI (rCDI) 6, 7.
- FMT can replenish intestinal microbiota and restore colonization resistance, offering a potential alternative to vancomycin for preventing rCDI 6.
- A treatment protocol involving FMT and continued vancomycin in selected patients has shown high success rates for severe and severe/complicated CDI 7.