Treatment of C. difficile Infection

Initial Treatment

For initial episodes of C. difficile infection, the Infectious Diseases Society of America recommends oral vancomycin (125 mg four times daily for 10 days) or fidaxomicin (200 mg twice daily for 10 days) as first-line treatments, with fidaxomicin being preferred due to lower recurrence rates 1, 2
Vancomycin 125 mg orally four times daily for 10 days is an alternative first-line option for non-severe CDI 1
Metronidazole 500 mg orally three times daily for 10 days can be considered in resource-limited settings, but has lower efficacy than vancomycin, particularly in severe cases 3, 4

Vancomycin 125 mg orally four times daily for 10 days is recommended for severe CDI 1, 3
Fidaxomicin 200 mg orally twice daily for 10 days is an alternative with lower recurrence rates for severe CDI 3

Vancomycin 500 mg orally four times daily plus intravenous metronidazole 500 mg three times daily is recommended for fulminant CDI or complicated infection 1, 5
For patients unable to take oral medications, intravenous metronidazole 500 mg three times daily plus vancomycin retention enema 500 mg in 100 mL normal saline four times daily is recommended 5, 6

Fidaxomicin 200 mg orally twice daily for 10 days is the preferred option for first recurrence 1
Vancomycin as a tapered and pulsed regimen rather than a standard 10-day course is recommended for first recurrence 1, 7
Fecal microbiota transplantation (FMT) is strongly recommended after at least 2 recurrences that have failed appropriate antibiotic treatments 1, 7

Discontinue the inciting antibiotic agent(s) as soon as possible to improve treatment outcomes 2
Avoid repeated metronidazole courses due to risk of cumulative and potentially irreversible neurotoxicity 2, 7

In severe CDI, vancomycin has demonstrated superior cure rates compared to metronidazole (97% vs. 76%) 3

Clinical response typically requires 3-5 days after starting therapy 2
Approximately 20% of patients experience recurrence, with higher risk in elderly patients and those with continued antibiotic use 2