What is a commonly used antibiotic for the treatment of Crohn's disease?

• A. Metronidazole
• B. Ciprofloxacin
• C. Amoxicillin
• D. Aztreonam

Answer: (A)

Antibiotics in Crohn’s disease are most helpful when there is infection or bacterial involvement driving inflammation, such as in perianal fistulas or abscesses. Metronidazole is effective against anaerobic bacteria commonly found in the gut and in fistulous tracts, making it a go-to option for fistulizing Crohn’s disease. Because of its anaerobic coverage, it can reduce drainage and promote healing, and it’s often used either alone or in combination with ciprofloxacin to broaden antimicrobial coverage when fistulas are present.

Ciprofloxacin can be used in Crohn’s, especially for certain fistulous or complicated cases, but metronidazole is the more commonly used agent for addressing anaerobic organisms and perianal disease, which is why it’s the best choice here. Amoxicillin is not typically used for Crohn’s management in this context, and aztreonam lacks the anaerobic coverage that is particularly beneficial for Crohn’s-related fistulas.