What are treatment options for Small Intestine Bacterial Overgrowth (SIBO) other than Xifaxan (Rifaximin)?

From the Guidelines

Treatment for Small Intestinal Bacterial Overgrowth (SIBO) beyond Xifaxan (rifaximin) includes several effective alternatives, with metronidazole, amoxicillin-clavulanate, and doxycycline being commonly used antibiotics as per the ESPEN practical guideline 1. When considering treatment options, it's crucial to prioritize the reduction of morbidity, mortality, and improvement of quality of life.

• Metronidazole (250-500mg three times daily for 10-14 days) is effective for hydrogen-predominant SIBO.
• Amoxicillin-clavulanate (875/125mg twice daily for 10-14 days) offers broad-spectrum coverage.
• Doxycycline is another option, as mentioned in the guideline 1. The management of SIBO also involves addressing potential complications such as diarrhea and bile salt malabsorption, for which medications like loperamide, and bile salt sequestrants (cholestyramine and colesevelam) may be used, as suggested in the management of adult patients with severe chronic small intestinal dysmotility 1. It's also important to consider the risk of resistant organisms, including Clostridioides difficile, and the potential side effects of long-term antibiotic use, such as peripheral neuropathy with metronidazole and tendonitis with ciprofloxacin 1. Dietary modifications, including a low FODMAP diet, and prokinetics like low-dose erythromycin or prucalopride, can help prevent recurrence by improving intestinal motility. Overall, the choice of treatment should be based on the individual patient's needs and the severity of their symptoms, with the goal of reducing morbidity, mortality, and improving quality of life.

From the FDA Drug Label

CLINICAL PHARMACOLOGY Neomycin sulfate is poorly absorbed from the normal gastrointestinal tract. ... Growth of most intestinal bacteria is rapidly suppressed following oral administration of neomycin sulfate, with the suppression persisting for 48 to 72 hours. Microbiology In vitrotests have demonstrated that neomycin is bactericidal and acts by inhibiting the synthesis of protein in susceptible bacterial cells. It is effective primarily against gram-negative bacilli but does have some activity against gram-positive organisms.

SIBO Treatment: Neomycin can be considered as a treatment option for SIBO, as it suppresses the growth of intestinal bacteria. However, it is essential to note that neomycin is not active against anaerobic bowel flora, which may be a component of SIBO.

• The treatment effect of neomycin on SIBO may be limited to its activity against gram-negative bacilli and some gram-positive organisms.
• The use of neomycin for SIBO treatment should be approached with caution, considering its potential limitations and the specific characteristics of the patient's condition 2.

From the Research

SIBO Treatment Options

Other than Xifaxin, the following treatment options are available for SIBO:

• Metronidazole: a study published in 2009 compared the efficacy of rifaximin and metronidazole in treating SIBO, and found that rifaximin had a higher SIBO decontamination rate than metronidazole 3
• Other antibiotics: a systematic review and meta-analysis published in 2017 found that rifaximin was effective and safe for the treatment of SIBO, but also identified other factors that could influence the eradication rate, such as drug dose and study design 4

Efficacy of Rifaximin

Rifaximin has been shown to be effective in treating SIBO in several studies:

• A study published in 2007 found that rifaximin was safe and effective in reducing symptoms in patients with SIBO, especially when diarrhea was the dominant symptom 5
• A study published in 2019 found that rifaximin was effective in treating hydrogen-positive SIBO, with a response rate of 47.4% for hydrogen positivity alone and 80% for both hydrogen and methane positivity 6
• A systematic review and meta-analysis published in 2021 found that rifaximin had an overall eradication rate of 59% according to intention-to-treat analysis, and 63% according to per protocol analysis 7

Comparison with Other Treatments

Comparisons between rifaximin and other treatments for SIBO have been made in several studies:

• A study published in 2009 compared rifaximin with metronidazole and found that rifaximin had a higher SIBO decontamination rate and fewer adverse events 3
• A systematic review and meta-analysis published in 2021 found that there was no significant difference in efficacy between rifaximin and placebo or active controls in 5 RCTs included in the analysis 7