oral Metronidazole failure in c-diff.

Q: What usually leads to failure of oral metronidazole in clostridioides difficile infection? 

Answer:Although not completely clear but it appears that oral metronidazole has a capacity to get well absorbed, which turns out to be a cause of failure! As colonic inflammation improves and metronidazole stool level decreases (due to increase gut absorption), treatment failure may ensues. 

In contrast, oral vancomycin or fidaxomicin is very poorly absorbed from the gut. Their stool drug level remains high leading to a better prospect of treatment in clostridioides difficile infection.

#GI

#ID

#pharmacology

References:

1. Musher DM, Aslam S, Logan N, et al. Relatively poor outcome after treatment of Clostridium difficile colitis with metronidazole. Clin Infect Dis 2005; 40:1586.

2. Hu MY, Maroo S, Kyne L, et al. A prospective study of risk factors and historical trends in metronidazole failure for Clostridium difficile infection. Clin Gastroenterol Hepatol 2008; 6:1354.

3. Bolton RP, Culshaw MA. Faecal metronidazole concentrations during oral and intravenous therapy for antibiotic associated colitis due to Clostridium difficile. Gut 1986; 27:1169.

4. Appaneal HJ, Caffrey AR, LaPlante KL. What Is the Role for Metronidazole in the Treatment of Clostridium difficile Infection? Results From a National Cohort Study of Veterans With Initial Mild Disease. Clin Infect Dis 2019; 69:1288.