Evaluation of the effect of rifaximin in colon diverticular disease by means of lactulose hydrogen breath test.

To understand better the mechanism by which rifaximin produces symptomatic relief in diverticular disease of the colon, the effect of this antibiotic on orocaecal transit time and on the production of hydrogen by intestinal microflora after ingestion of lactulose was studied in 33 patients with this disease and in 11 healthy subjects. An hydrogen breath test was carried out to measure pulmonary hydrogen excreted during the 3 hours after ingestion of 10 g lactulose. In patients, the hydrogen breath test with lactulose was repeated after treatment with 400 mg rifaximin twice daily for 10 days. In patients under basal conditions and controls, orocaecal transit time did not differ significantly, but hydrogen production was significantly higher in the former (p < 0.02). In patients, transit time and hydrogen excretion in response to lactulose administration did not differ significantly before and after treatment with rifaximin, and these two parameters were inversely correlated both before (r = 0.49, p < 0.01) and after rifaximin (r = 0.58, p < 0.001). Fifteen of the 33 patients showed accelerated transit time after treatment with the antibiotic, 10 showed no variation, and 8 showed prolonged transit. In 19 patients a reduction in hydrogen production was noted after rifaximin, while in 14 an increase was demonstrated. Twenty-one of the 33 patients reported an improvement in their symptoms with rifaximin; of these, only 10 showed accelerated transit time and 9 a reduction in hydrogen production after rifaximin.(ABSTRACT TRUNCATED AT 250 WORDS)