Rifaximin (Xifaxan)
Gut · Gut-selective antibiotic
Tier A-
What this is
Expensive branded product (Xifaxan) — Salix/Bausch has defended patent aggressively; generics have started appearing 2024+. One of few antibiotics safe enough to use more than once without undue resistance/dysbiosis concerns due to gut-confined action. Repeat courses often needed in SIBO (not FDA-approved for SIBO but widely used off-label).
Mechanism
Non-absorbable (~0.4% systemic absorption) rifamycin derivative; broad-spectrum antibacterial confined to gut lumen; FDA-approved for traveler's diarrhea, IBS-D, hepatic encephalopathy
Dose & route
550 mg PO 3x/day for 14 days (IBS-D); 1100 mg 2x/day (hepatic encephalopathy)
Citations
- https://pubmed.ncbi.nlm.nih.gov/21208106/
- https://pubmed.ncbi.nlm.nih.gov/27102054/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC5638048/
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This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.