From the Guidelines
Methane dominant Small Intestinal Bacterial Overgrowth (SIBO) is best treated with a combination of antibiotics targeting the methane-producing organisms, such as rifaximin 550mg three times daily plus neomycin 500mg twice daily for 14 days, as this regimen has been shown to be effective in reducing symptoms and improving quality of life 1. The treatment of methane dominant SIBO requires a comprehensive approach that includes antibiotics, dietary modifications, and prokinetic agents.
- Antibiotics: The recommended treatment regimen is rifaximin 550mg three times daily plus neomycin 500mg twice daily for 14 days. Alternatively, rifaximin can be combined with metronidazole 250mg three times daily for 14 days if neomycin is unavailable 1.
- Dietary modifications: Following a low FODMAP diet during and after treatment can help reduce fermentable carbohydrates that feed the bacteria, thereby reducing symptoms and improving quality of life.
- Prokinetic agents: Low-dose erythromycin (50mg at bedtime), prucalopride, or motegrity can help prevent recurrence by improving intestinal motility. It is also important to note that probiotics may have a beneficial effect on gut health, particularly in maintaining a healthy balance of microorganisms in the gut, although their use in methane dominant SIBO is not well established 1. Methane SIBO is typically more difficult to treat than hydrogen-dominant SIBO because methanogens (Archaea) are not bacteria but a different microorganism entirely, and they often form biofilms that protect them from antibiotics. These methanogens convert hydrogen to methane gas, resulting in the characteristic constipation rather than diarrhea seen in hydrogen SIBO. Treatment success should be monitored through symptom improvement and can be confirmed with follow-up breath testing 4-6 weeks after completing antibiotics.
From the Research
Methane Dominant SIBO Treatment
- Methane dominant SIBO is a condition where the small intestine has an overgrowth of bacteria that produce methane, leading to symptoms such as bloating, gas, and abdominal pain 2, 3, 4, 5, 6.
- Rifaximin is a broad-range, gastrointestinal-specific antibiotic that has been shown to be effective in treating SIBO, including methane dominant SIBO 2, 3, 5.
- Studies have shown that rifaximin can improve symptoms and eradicate SIBO in up to 84% of patients, with results sustained up to 10 weeks post-treatment 3.
- However, rifaximin may be less effective in methane-positive subjects, and a combination of rifaximin and neomycin may be more effective in treating methane-producing subjects 6.
- Alternative therapies such as probiotics, therapeutic diets, and herbal medicines have also been used to treat SIBO, but more research is needed to determine their effectiveness 4.
Treatment Options
- Rifaximin: 550 mg three times daily for 14 days 2, or 800 mg per day for 4 weeks 5.
- Neomycin: 500 mg twice daily for 10 days 6.
- Combination of rifaximin and neomycin: rifaximin 400 mg three times daily and neomycin 500 mg twice daily for 10 days 6.
- Probiotics, therapeutic diets, and herbal medicines: may be used as alternative or adjunctive therapies, but more research is needed to determine their effectiveness 4.
Efficacy of Treatment
- Rifaximin: 47.4% response rate for hydrogen positivity alone, and 80% response rate for both hydrogen and methane positivity 2.
- Rifaximin: 85.7% of patients with diarrhea reported improvement in symptom scores of more than 50% 5.
- Combination of rifaximin and neomycin: 85% of subjects had a clinical response, and 87% of subjects eradicated the methane on their breath test 6.