Small intestinal bacterial overgrowth: Management
- Mark Pimentel, MD, FRCP(C)
Mark Pimentel, MD, FRCP(C)
- Executive Director
- Medically Associated Science and Technology (MAST) Program
- Cedars-Sinai Medical Center
Small intestinal bacterial overgrowth (SIBO) is a condition in which the small bowel is colonized by excessive aerobic and anaerobic microbes that are normally present in the colon. The majority of patients with SIBO present with bloating, flatulence, abdominal discomfort, or diarrhea. This topic will review the management of SIBO. The etiology, pathogenesis, clinical manifestations, and diagnosis of SIBO are presented separately. (See "Small intestinal bacterial overgrowth: Clinical manifestations and diagnosis".)
The mainstay of therapy for SIBO are antibiotics to reduce (rather than eradicate) small intestinal bacteria. In addition, some patients require treatment of underlying nutritional deficiencies and associated ileitis/colitis.
Antibiotic therapy — Antibiotic therapy is typically begun on an empiric basis. The selection of antimicrobial regimens is based on the pattern of bacterial overgrowth, the prevalence of risk factors for drug-resistance (recent or repeated prior exposure), relevant antibiotic allergies, and cost . It is unnecessary to repeat breath testing if symptoms resolve with treatment. (See "Small intestinal bacterial overgrowth: Clinical manifestations and diagnosis", section on 'Carbohydrate breath test'.)
●Hydrogen-predominant bacterial overgrowth — In patients with hydrogen predominant bacterial overgrowth without excess methane production, we use rifaximin (1650 mg/day for 14 days). Rifaximin is nonabsorbable rifamycin derivative. It is well tolerated and has been demonstrated to be effective in the treatment of SIBO [2-8]. However, the high cost of rifaximin has limited its use.
●Methane-predominant bacterial overgrowth — In patients with methane-predominant bacterial overgrowth, we use a combination of neomycin 500 mg twice daily and rifaximin 550 mg three times daily for 14 days .
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- INITIAL APPROACH
- Antibiotic therapy
- Correction of micronutrient deficiency
- Treatment of associated ileocolitis
- TREATMENT RESPONSE AND RECURRENCE
- INADEQUATE RESPONSE TO INITIAL THERAPY OR RECURRENCE
- Subsequent antibiotic regimen
- Elemental diet
- PREVENTION OF RECURRENCE
- Treat the underlying etiology in all patients
- Antibiotic prophylaxis in selected patients
- Interventions with unclear role
- SUMMARY AND RECOMMENDATIONS