Role of Rifaximin (Rifagut) in Treating Colitis

Rifaximin has limited efficacy in treating colitis and should not be routinely used as primary therapy for inflammatory colitis conditions.

Types of Colitis and Rifaximin's Role

Rifaximin is not recommended as primary therapy for ulcerative colitis or Crohn's disease according to British Society of Gastroenterology guidelines 1
While rifaximin has shown some promise in inducing remission in IBD in open studies, larger controlled studies are needed to confirm its efficacy 2
Rifaximin resistance can develop in IBD-associated E. coli strains, especially with prior rifaximin use, which may limit its long-term effectiveness 3

Rifaximin (550 mg three times daily for 14 days) is approved as a second-line treatment for IBS-D in the USA, though not available for this indication in many countries 1
It shows modest efficacy for the FDA composite endpoint for IBS-D and stool consistency, but limited effect on abdominal pain 1
Retreatment with rifaximin is effective for patients with IBS-D who initially respond but later experience symptom recurrence 1, 4

The American Gastroenterological Association suggests against the use of rifaximin after acute uncomplicated diverticulitis (conditional recommendation, very low-quality evidence) 1
Despite some numerical reduction in recurrence rates in trials, results were not statistically significant 1

Rifaximin is effective for non-invasive travelers' diarrhea caused by diarrheagenic E. coli 1
However, it is less effective for invasive pathogens such as Campylobacter, Salmonella, and Shigella, with failure rates up to 50% 1
It should not be used for dysentery regardless of illness severity 1

Rifaximin is a non-absorbable antibiotic derivative of rifamycin that inhibits bacterial RNA synthesis 5
It has virtually no systemic absorption after oral administration, limiting systemic side effects 2, 5
It possesses good activity against Gram-positive bacteria (Staphylococcus, Streptococcus, Enterococcus) but less activity against Enterobacteriaceae 5

Rifaximin generally has a favorable safety profile with adverse events similar to placebo in clinical trials 1, 4
Headache is the most common adverse event, but overall side effects are no more common than with placebo 1
Concerns exist regarding potential for adverse events with repeated courses, including:
- Clostridium difficile infection (though studies show it may have a potential role in CDI management) 6
- Development of bacterial resistance 3

Combination therapy with probiotics (such as E. coli Nissle 1917) may enhance rifaximin's therapeutic effect in colitis, as demonstrated in animal studies 7
This synergistic effect warrants further investigation in human clinical trials 7

For IBD (ulcerative colitis or Crohn's disease): Do not use rifaximin as primary therapy; standard treatments recommended by gastroenterology guidelines should be used instead 1
For IBS-D: Consider rifaximin as a second-line option after conventional therapies fail, with potential for retreatment if symptoms recur after initial response 1
For travelers' diarrhea: Rifaximin may be used for non-invasive cases but is not appropriate for dysentery or invasive infections 1
For diverticulitis: Rifaximin is not recommended for routine use after acute uncomplicated diverticulitis 1

Assess whether diarrhea represents worsening of the original condition or a new adverse event in patients taking rifaximin 4
For persistent symptoms, consider the possibility of invasive pathogens not adequately covered by rifaximin 4
Monitor for development of resistance, particularly in patients with prior rifaximin exposure 3