From the Guidelines
Small intestinal bacterial overgrowth (SIBO) is best treated with a combination of antibiotics and dietary modifications, with rifaximin being the preferred antibiotic choice, as evidenced by recent studies 1. The primary treatment for SIBO involves a 14-day course of rifaximin (Xifaxan) 550 mg three times daily, which has been shown to be effective in reducing bacterial overgrowth and improving symptoms 1. For patients with predominantly methane-producing SIBO, adding neomycin 500 mg twice daily for the same duration may be beneficial 1. In addition to antibiotics, implementing a low FODMAP diet for 4-6 weeks can help reduce fermentable carbohydrates that feed bacteria, thereby alleviating symptoms 1. After this period, slowly reintroducing foods can help identify triggers. To prevent recurrence:
- Take a prokinetic agent like low-dose erythromycin (50 mg at bedtime) for 3 months to maintain proper motility 1.
- Address any underlying conditions, such as motility disorders or anatomical abnormalities, to prevent bacterial overgrowth 1.
- Consider intermittent courses of herbal antimicrobials, such as oregano oil or berberine, if symptoms return, although the evidence for their effectiveness is limited 1. SIBO occurs when bacteria typically found in the large intestine colonize the small intestine, leading to malabsorption and various gastrointestinal symptoms, including diarrhea, bloating, and abdominal pain 1. The antibiotic treatment aims to reduce bacterial overgrowth, while dietary changes and prokinetics help maintain a healthy gut environment and proper motility to prevent recurrence. Some key symptoms of SIBO include:
- Diarrhea
- Bloating
- Abdominal pain
- Malabsorption
- Weight loss
- Fatigue It is essential to note that the treatment of SIBO should be individualized, and the choice of antibiotic and dietary modifications may vary depending on the patient's specific needs and circumstances, as well as the severity of their symptoms 1.
From the Research
Symptoms of Small Intestinal Bacterial Overgrowth (SIBO)
- Non-specific abdominal discomfort
- Nutrient malabsorption
- Chronic intestinal and extraintestinal symptomatology
- Diarrhea
- Abdominal pain
Treatment Options for SIBO
- Rifaximin: a broad spectrum non-absorbable antibiotic, with doses of 1200 mg/day showing a decontamination rate of 60% with low side-effects incidence 2
- Rifaximin 1600 mg/day: showed a significantly higher efficacy for SIBO treatment with respect to 1200 mg with similar compliance and side-effect profile 2
- Metronidazole: an antibiotic that can be used to treat SIBO, but with a lower decontamination rate compared to rifaximin 3
- Berberine: a natural component that may provide therapeutic target for SIBO, with a study currently underway to evaluate its effect compared to rifaximin 4
- Herbal therapy: equivalent to rifaximin for the treatment of SIBO, with a remission rate of 46% compared to 34% for rifaximin 5
Efficacy of Treatment Options
- Rifaximin: showed a glucose breath test normalization rate of 63.4% compared to 43.7% for metronidazole 3
- Rifaximin: response rates of 47.4% for hydrogen positivity alone and 80% for both hydrogen and methane positivity 6
- Herbal therapy: appeared to be as effective as triple antibiotic therapy for SIBO rescue therapy for rifaximin non-responders 5
Safety and Tolerability of Treatment Options
- Rifaximin: showed a low incidence of side effects, with no significant differences in patient compliance and incidence of side effects compared to metronidazole 2, 3
- Metronidazole: had a higher incidence of adverse events compared to rifaximin 3
- Herbal therapy: reported only one case of diarrhea, which did not reach statistical significance 5