1184 Durability of Rifaximin in the Treatment of Small Intestine Bacterial Overgrowth

Abstract

INTRODUCTION: Multiple antibiotics have been evaluated in the treatment of small intestinal bacterial overgrowth (SIBO). Although the response rates vary by treatment, the overall duration of response has not been clearly defined. Rifaximin (Xifaxan, Salix, Bridgewater, New Jersey, USA) has demonstrated potent activity against numerous pathogenic bacteria. We report our clinical experience with Rifaximin as a durable treatment option for SIBO. METHODS: 205 records from 9 physicians at a single center were reviewed retrospectively. Chart review was performed from January 2010 through present. Patients underwent hydrogen breath testing in accordance with current consensus recommendations. Patients who were treated with Rifaximin were included for review. Patients less than 18 years old or those with incomplete follow up data were excluded. Patient demographics, antibiotic regimen, response to therapy, and duration of follow up were recorded. Clinical response was defined as patient reported response to underlying symptom (bloating, flatulence, pain, diarrhea) and physician assessment. Duration of response was defined as time to recurrence of initial symptoms from date of antibiotic treatment. Adverse events were defined as patient reported symptoms during treatment. Data were summarized and analyzed using Microsoft Excel v14.7.2. Chi-squared analysis was performed where appropriate. RESULTS: 156 patients met criteria for review. One hundred twenty-two (78%) were women and 34 (22%) were men. The average age was 52 +/- 19 years. Most patients were treated with 550mg twice daily dosing (n = 108, 69%) with 10 days being the most common duration (n = 68, 44%). Forty-eight patients (31%) were treated with TID dosing for 7,10, or 14 days duration. Symptom relief was observed in 77% of all patients (n = 120). The median duration of symptom relief was 6 months (range 1-96), with a mean follow up time of 14 months. Response was not significantly different when stratified by gender (79% vs 67% for women and men, respectively; P = 0.15). BID dosing was associated with symptom improvement compared to TID dosing (83% vs 63%, P = 0.004). Side effects included: nausea (1.9%), diarrhea (1.3%), oral thrush (1.3%) and abdominal pain (0.6%). CONCLUSION: Treatment with Rifaximin resulted in clinical improvement in the majority of patients with SIBO. The median duration of symptom relief with Rifaximin treatment was 6 months. Further prospective data is needed to identify the optimal dosing regimen to maximize durability.