THE EFFECT OF RIFAXIMIN TREATMENT FOR SMALL INTESTINAL BACTERIAL OVERGROWTH ON THYROID DISORDERS

Introduction. Clinical findings indicate frequent coexistence of small intestinal bacterial overgrowth (SIBO) and autoimmune thyroiditis. However, the causal relationship of these diseases has not been confirmed. The aim of the study was to assess the effect of rifaximin treatment of SIBO on thyroid function. Material and methods. The study included 146 patients, aged 25-68 years, with diagnosed SIBO on the basis of lactulose hydrogen breath test (LHBT). Furthermore, in 62 patients the levels of free triiodothyronine and thyroxine (FT3, FT4) or thyroid-stimulating hormone (TSH) and anti-thyroid peroxidase antibodies (ATPO) deviated from the accepted laboratory standards. From this group 32 patient with predominant diarrhea (group I) and 30 patients with predominant constipation (group II) were admitted for further evaluation. Rifaximin at 3x 400 mg was used for 7 days and this cycle was repeated 3 times every 28 days. Results were assessed after 3 months. Results. After 3 months the result of LHBT decreased in group I by 72,1% and in group II by 76,3%. A positive correlation between the results of LHTB and the level of ATPO was observed, partially in II group. After the treatment the level of ATPO decreased in group I from 31.9 ± 23.4 to 19.4 ± 19.7 ± 13.4 IU/ml (p < 0,05) and in group II from 94.1 ± 56.3 to 23.4 ± 13.3 IU/ml (p < 0,01). In group II the level of TSH also decreased from 5.1 ± 0.9 to 3.7 ± 1.8 mU/L (p < 0,01). Conclusion. Rifaximin treatment of small intestinal bacterial overgrowth improves thyroid disorders