A combination of rifaximin and neomycin is most effective in treating irritable bowel syndrome patients with methane on lactulose breath test.
OBJECTIVE
There is a growing interest in methane and its association with constipation in functional bowel disease. Neomycin-based treatment of methane-positive subjects has resulted in improvement of constipation. Rifaximin, although superior for the treatment of irritable bowel syndrome compared with other antibiotics, seems less effective in methane-positive subjects. In this study, we evaluate 3 different antibiotic treatments in patients who have a methane-positive breath test: rifaximin only, neomycin only, and the combination of neomycin and rifaximin.


METHODS
A retrospective chart review was conducted on patients with methane on their lactulose breath test (> or =3 ppm of methane) who received one of the following antibiotic treatments: 500 mg b.i.d. for 10 days of neomycin alone, 400 mg t.i.d. for 10 days of rifaximin alone, or a combination of both rifaximin and neomycin for 10 days. All patients must have received antibiotic treatment after their initial consultation at the medical center and, in addition, had at least 1 follow-up to evaluate the effects of the treatment. After inclusion/exclusion criteria were met, all charts were evaluated to determine if the subject was a responder to the antibiotic therapy. This included clinical symptom improvement and eradication of methane on their breath test.


RESULTS
Of the subjects receiving the treatment of rifaximin and neomycin (n=27), 85% had a clinical response, compared with 63% of subjects in the neomycin only group (n=8) (P=0.15) and 56% of subjects in the rifaximin only group (n=39) (P=0.01). When comparing the neomycin group with the rifaximin group, the difference was nonsignificant. When evaluating methane eradication results, 87% of subjects taking the rifaximin and neomycin combination eradicated the methane on their breath test. This is compared with 33% of subjects in the neomycin group that eradicated the methane (P=0.001), and only 28% of subjects in the rifaximin group (P=0.001). Of the patients who did not eliminate the methane with only rifaximin treatment, 66% of those who subsequently used the rifaximin and neomycin treatment were able to normalize their breath test.


CONCLUSIONS
The combination of rifaximin and neomycin is more effective in treating methane-producing subjects-in both clinical response and methane elimination.
Low
Kimberly
K
GI Motility Program, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
Hwang
Laura
L
Hua
Johnson
J
Zhu
Amy
A
Morales
Walter
W
Pimentel
Mark
M
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001944:Breath Tests / Q000379:methods; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008697:Methane / Q000378:metabolism*; D008875:Middle Aged; D009355:Neomycin / Q000008:administration & dosage / Q000627:therapeutic use*; D012189:Retrospective Studies; D012294:Rifamycins / Q000008:administration & dosage / Q000627:therapeutic use*; D000078262:Rifaximin; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D012294:Rifamycins; D009355:Neomycin; D000078262:Rifaximin; D008697:Methane