What antibiotics are used to treat colitis (inflammation of the colon)?

From the Guidelines

Antibiotics should be used to treat colitis only when the underlying cause is a bacterial infection, such as Clostridioides difficile, and the first-line treatment for C. difficile infection is oral vancomycin (125 mg four times daily for 10-14 days) or fidaxomicin (200 mg twice daily for 10 days) 1. When considering the use of antibiotics for colitis, it is essential to identify the underlying cause of the condition, as inappropriate use can worsen certain types of colitis or lead to antibiotic resistance.

• For ulcerative colitis and Crohn's disease (inflammatory bowel diseases), antibiotics are generally not recommended as primary therapy, and anti-inflammatory medications, immunosuppressants, or biologics are more appropriate treatments that address the underlying immune dysfunction.
• For infectious colitis caused by bacteria like Clostridioides difficile, antibiotics are essential, and oral vancomycin or fidaxomicin are preferred treatments.
• The use of antibiotics can disrupt gut flora, potentially exacerbating inflammatory bowel disease, and therefore, their use should be carefully considered and monitored. The most recent and highest quality study recommends the use of oral vancomycin or fidaxomicin for the treatment of C. difficile infection, and this should be the preferred treatment approach 1. In cases where the patient has a severe C. difficile infection, high-dose vancomycin (500 mg, 6 hourly), oral and/or by enema, in combination with intravenous metronidazole (500 mg, 8 hourly) may be considered 1. It is crucial to note that the use of antibiotics for colitis should always be guided by the underlying cause of the condition and the severity of the infection, and the treatment approach should be individualized to ensure the best possible outcome for the patient.

From the FDA Drug Label

Vancomycin Hydrochloride Capsules are indicated for the treatment of C. difficile-associated diarrhea. Vancomycin Hydrochloride Capsules are also used for the treatment of enterocolitis caused by Staphylococcus aureus (including methicillin-resistant strains) in adult and pediatric patients less than 18 years of age Vancomycin Hydrochloride Capsules for the treatment of colitis are for oral use only and are not systemically absorbed.

Vancomycin can be used to treat colitis caused by C. difficile or Staphylococcus aureus. The recommended dose for C. difficile-associated diarrhea is 125 mg administered orally 4 times daily for 10 days, and for staphylococcal enterocolitis, the total daily dosage is 500 mg to 2 g administered orally in 3 or 4 divided doses for 7 to 10 days 2.

From the Research

Antibiotics for Colitis

• The use of antibiotics for colitis depends on the cause and severity of the infection 3, 4, 5, 6, 7.
• For infectious colitis, standard stool culture should be performed to determine the cause of the infection, and pathogen-specific antimicrobial therapy should be initiated 3.
• For empiric treatment of febrile dysenteric diarrhea, invasive bacterial enteropathogens such as Shigella, Salmonella, and Campylobacter should be suspected, and adults may be treated empirically with 1000mg azithromycin in a single dose 3.
• For Clostridium difficile infection (CDI), metronidazole is regarded as the agent of choice for mild to moderate CDI, while vancomycin is recommended as an initial therapy for patients with severe CDI 4, 6, 7.
• Fidaxomicin is also available for clinical use and is as effective as vancomycin with lower relapse rates 4, 7.
• Rifaximin and fecal bacteriotherapy are alternative approaches in patients with severe or refractory CDI, before surgical intervention 4, 7.

Treatment Outcomes

• Patients with inflammatory bowel disease (IBD) and CDI have worse outcomes, including increased readmissions, colectomy, and death 6.
• Patients with ulcerative colitis (UC) and nonsevere CDI had fewer readmissions and shorter lengths of stay when treated with a vancomycin-containing regimen compared to those treated with metronidazole alone 6.
• Vancomycin is recommended for the treatment of severe CDI, while metronidazole is the standard of care for nonsevere infection 6.

Antibiotic Options

• Metronidazole is suitable for the treatment of mild forms of CDI, but vancomycin kills clostridia reliably and is recommended for severe CDI 4, 7.
• Fidaxomicin works faster than vancomycin and is associated with a lower risk of recurrence, making it a profitable option for patients with impending ileus or those who cannot undergo prolonged treatment 7.
• Rifaximin does not have a clear place in the treatment of CDI due to limited data on its efficacy and the risk of resistance 7.
• Tigecycline is a promising antibiotic for parenteral use, potentially more effective than intravenous metronidazole 7.