Episode Overview

Episode Title: SIBO Part III: Treatment
Podcast: Run the List
Date: December 15, 2025
Hosts: Allie Shebe (Guest Host), Dr. Navin Kumar (Guest, Gastroenterologist)

The final installment in Run the List's SIBO series focuses on the treatment and management of Small Intestinal Bacterial Overgrowth (SIBO). Guest host and Harvard medical student Allie Shebe is joined by Dr. Navin Kumar to offer a thorough, practical guide to SIBO therapy, including antibiotics, dietary considerations, and supportive strategies. Emphasis is placed on real-world application, patient counseling, and integrating recent guidelines into practice.

Key Discussion Points & Insights

1. Recap & Case Introduction ([01:22])

• Allie Shebe: Reviews SIBO diagnosis and introduces Ms. R, a case of a 45-year-old woman with post-Roux-en-Y gastric bypass and SIBO confirmed by breath testing.
• Diagnostic Criteria: Hydrogen ≥20 ppm rise or methane ≥10 ppm on lactulose breath test.

2. Antibiotic Selection by SIBO Subtype ([02:20])

Hydrogen-Predominant SIBO

• Preferred Antibiotic: Rifaximin (Xifaxan)

  • Dose: 550 mg three times daily for 14 days
  • "It's a non-absorbable antibiotic that has gram positive, gram negative, and anaerobic coverage, and it effectively decreases the bacterial population of the small bowel." — Dr. Kumar [03:08]
  • Less systemic side effects; primary site of action is the intestinal tract.
  • Common Adverse Effects: GI upset, diarrhea, occasional lightheadedness.
  • Notable Issue: High cost if not covered by insurance.
    • "Do not fill it if it's not covered by insurance because the cost is very, very high." — Dr. Kumar [04:18]

• Alternatives (if rifaximin not available/covered):

  • Augmentin (Dr. Kumar’s next line due to safety)
  • Metronidazole, Ciprofloxacin, or Bactrim (all with similar efficacy) [04:27]

Methane-Predominant SIBO

• Recommended Regimen: Rifaximin + Neomycin
  • Rifaximin: 550 mg TID x 14 days
  • Neomycin: 500 mg BID x 14 days
• Risks of Neomycin:
  • Ototoxicity (can be permanent tinnitus/ringing), kidney injury, nerve damage
    • "The one I've actually seen occur is the ototoxicity, which manifests with a permanent tinnitus or ear ringing of the ear. So it's really important to counsel your patients about the potential side effects of neomycin because they are serious and as I mentioned, they can be permanent." — Dr. Kumar [06:09]
  • Check for pre-existing hearing, renal, or nerve issues before prescribing.
  • Higher rate of GI upset; recommend to take with food.
• Clinical Pearls:
  • Some may opt to try rifaximin alone to minimize risk.
    • "It's always a risk-benefit discussion with the addition of neomycin because of those potentially permanent and damaging side effects." — Dr. Kumar [06:54]

3. Non-Antibiotic Strategies: Diet & Supportive Care ([07:27])

• Low FODMAP Diet:
  • Focus: Reduce intake of fermentable oligo-, di-, monosaccharides and polyols, which feed small intestinal bacteria.
  • Resource Recommendation: www.katescarlotta.com for practical diet guides.
    • "What I love about it shows options of foods that they can have and then foods that they should try to avoid." — Dr. Kumar [08:12]
  • Challenges: Many forbidden foods (e.g., broccoli, cauliflower) are otherwise nutritious; balance is key.
  • Dietitian referral recommended for sustainable dietary planning.
• Probiotics:
  • Not recommended for SIBO treatment — lack of robust evidence.
    • "Our current national guidelines suggest to not use probiotics because the evidence is so limited for benefit to patients. So as a result, we are not recommending probiotics as a mainstay of diet therapy for sibo." — Dr. Kumar [09:12]
• Symptom Relief:
  • Peppermint oil and simethicone for gas and bloating symptom management.

4. Clinical Pearls & Practical Takeaways ([10:50])

Dr. Kumar’s "Three Key Takeaways":

1. Identify SIBO Subtype: Hydrogen vs. methane influences antibiotic selection.
2. Rifaximin as First-Line: Best-studied and safest; adjunct neomycin only for methane-predominant, weighing risks.
3. Diet Matters: Low FODMAP diet recommended for all, especially those avoiding antibiotics; refer to nutrition for support.

• "Given the benefit of adhering to a low fodmap diet for all patients, and particularly those who prefer to avoid antibiotics, think about referring your patients to nutrition to help modify their diets in a safe and healthy manner." — Dr. Kumar [11:23]

Notable Quotes & Memorable Moments

• Rifaximin Side Effects:
  "In my experience, the most common side effects that patients may have on rifaximin are GI upset and diarrhea, because again, the main area of action is within the intestinal tract." — Dr. Kumar [03:42]

• On the high cost of rifaximin:
  "Do not fill it if it’s not covered by insurance because the cost is very, very high." — Dr. Kumar [04:18]

• On neomycin’s risk profile:
  "It's really important to counsel your patients about the potential side effects of neomycin because they are serious and as I mentioned, they can be permanent." — Dr. Kumar [06:09]

• On probiotics:
  "Our current national guidelines suggest to not use probiotics because the evidence is so limited for benefit to patients." — Dr. Kumar [09:12]

• On utilizing dietitians:
  "It makes a lot of sense if it’s available to your patients to refer them to nutrition. The dietitians can be very helpful in helping to guide patients." — Dr. Kumar [08:23]

Timestamps for Important Segments

• [01:22] Recap of SIBO diagnosis; case presentation
• [02:20] Hydrogen-predominant SIBO: Antibiotic choices, rationale
• [04:50] Alternatives when rifaximin is unavailable
• [05:05] Methane-predominant SIBO: Double antibiotic regimen, side effect counseling
• [07:27] Non-antibiotic strategies: Low FODMAP diet, role of probiotics, symptomatic treatments
• [10:50] Summary pearls: subtype identification, antibiotic regimens, importance of diet and nutritionist referral

Summary Table

| Topic/Question | Segment Start | Key Takeaways | |----------------------------------------------|---------------|------------------------------------------------------------------------------------------------| | Diagnosis & Case Presentation | [01:22] | SIBO defined, diagnostic thresholds, case: Ms. R | | Hydrogen-Predominant SIBO Treatment | [02:20] | Rifaximin preferred, dose details, cost considerations, alternatives if needed | | Methane-Predominant SIBO Treatment | [05:05] | Rifaximin + Neomycin, detailed side effect counseling, when to avoid neomycin | | Non-Antibiotic Approaches | [07:27] | Low FODMAP diet, referral to dietitian, probiotics not recommended, symptom relief (peppermint, simethicone)| | Clinical Pearls & Takeaways | [10:50] | Subtype matters, rifaximin as first-line, always consider diet, importance of nutritionist |

Final Takeaways

• Personalize SIBO treatment based on diagnostic breath test findings (hydrogen vs. methane patterns).
• Antibiotics remain primary therapy, with rifaximin favored for safety and efficacy — but carefully review cost and insurance coverage.
• Methane-predominant SIBO may require a risk–benefit discussion about adding neomycin due to serious potential side effects.
• Dietary modification (low FODMAP) is important for all SIBO patients; refer to dietitians for best results.
• Probiotics are not routinely recommended due to lacking evidence.
• Supportive symptom management (peppermint oil, simethicone) can be offered for gas/bloating.

For additional resources on SIBO diets:

• www.katescarlotta.com

For further learning, check out episodes I and II in the Run the List SIBO series.