What to do if a patient experiences diarrhea while taking Rifaximin (Rifaximin)?

Management of Diarrhea in Patients Taking Rifaximin

For patients experiencing diarrhea while taking rifaximin, the recommended approach is to discontinue the medication if diarrhea persists more than 24-48 hours or worsens, and seek medical care for fever and/or blood in the stool. 1

Assessment of Diarrhea in Rifaximin Users

When a patient on rifaximin presents with diarrhea, consider the following:

• Evaluate for Clostridioides difficile-associated diarrhea (CDAD), which can occur with rifaximin use, though it's relatively uncommon compared to other antibiotics 1
• Assess for bloody stools and fever, which may indicate a more serious condition requiring immediate medical attention 1
• Determine if diarrhea represents worsening of the original condition being treated (e.g., IBS-D) or a new adverse event 2
• Consider the timing of diarrhea onset in relation to rifaximin treatment initiation 2

Management Algorithm

1. For Travelers' Diarrhea Patients:

• Discontinue rifaximin if diarrhea persists more than 24-48 hours or worsens 1
• Seek medical care immediately for fever and/or blood in stool 1
• Consider that persistent diarrhea may indicate an invasive pathogen not adequately covered by rifaximin 2

2. For IBS-D Patients:

• Assess whether diarrhea represents treatment failure or an adverse event 2
• If symptoms worsen or change in character from baseline IBS-D symptoms, consider discontinuation 2
• For patients who initially responded to rifaximin but experience recurrent symptoms:
  • Retreatment with rifaximin is recommended at the same dosage (550 mg three times daily for 14 days) 2
  • Patients can be retreated up to 2 additional times with the same dosage regimen 2

3. For All Patients - Monitor for C. difficile Infection:

• Be vigilant for CDAD, which can occur during or even months after treatment 1
• Symptoms include watery or bloody diarrhea with or without stomach cramps and fever 1
• If CDAD is suspected, stop rifaximin and initiate appropriate testing and treatment 1

Special Considerations

• The safety profile of rifaximin is generally favorable, with adverse events similar to placebo in clinical trials 2
• Rifaximin has low systemic absorption (<0.4%), which contributes to its favorable safety profile 3
• For IBS-D patients, rifaximin may actually improve diarrhea as part of its therapeutic effect 4, 5
• Rifaximin is less effective against invasive enteric pathogens, which may explain treatment failures in some cases of travelers' diarrhea 2, 3

Pitfalls and Caveats

• Do not confuse treatment failure with antibiotic-associated diarrhea; proper assessment is crucial 1
• Rifaximin is primarily effective against non-invasive diarrheagenic pathogens; persistent symptoms may indicate an invasive pathogen requiring different antimicrobial therapy 2
• Patients should be counseled that antibiotics should only be used to treat bacterial infections, not viral infections 1
• Incomplete courses of therapy may decrease effectiveness and increase the likelihood of bacterial resistance 1
• While rifaximin has a lower risk of C. difficile infection compared to systemic antibiotics, vigilance is still required 1, 6