Rankings / Immune & Inflammation
Rifaximin (Xifaxan)
Immune & Inflammation · Gut-selective antibiotic
Tier A+
Bottom line
Read Off Label grades Rifaximin (Xifaxan) as A+ (8.4/10) based on strong evidence, strong benefit magnitude, and a low-risk safety profile.
Expensive branded product (Xifaxan) — Salix/Bausch has defended patent aggressively; generics have started appearing 2024+.
Studied, labeled, or reported-use context: 550 mg PO 3x/day for 14 days (IBS-D); 550 mg PO 2x/day (hepatic encephalopathy per US labeling) — Rx; not individualized guidance.
What the evidence says
Expensive branded product (Xifaxan) — Salix/Bausch has defended patent aggressively; generics have started appearing 2024+. Minimal systemic absorption changes its adverse-effect profile relative to systemic antibiotics, but repeat-course resistance and microbiome effects remain areas of concern. Repeat courses have been studied and are used in some contexts; SIBO remains 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
Studied, labeled, or reported dose & route
550 mg PO 3x/day for 14 days (IBS-D); 550 mg PO 2x/day (hepatic encephalopathy per US labeling)
This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.
Citations
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Common questions
- What does the evidence show about Rifaximin (Xifaxan)'s effects?
- Read Off Label rates the evidence for Rifaximin (Xifaxan) as Strong and the benefit magnitude as strong, producing an overall grade of A+ (8.4/10). Expensive branded product (Xifaxan) — Salix/Bausch has defended patent aggressively; generics have started appearing 2024+.
- What safety findings are reported for Rifaximin (Xifaxan)?
- Rifaximin (Xifaxan) has a low risk profile in the database. Low (minimal systemic effect; C. diff risk lower than systemic antibiotics but not zero; resistance concerns with repeated courses) Legal status: Rx.
- What doses or routes are reported for Rifaximin (Xifaxan)?
- 550 mg PO 3x/day for 14 days (IBS-D); 550 mg PO 2x/day (hepatic encephalopathy per US labeling) This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
- How does Rifaximin (Xifaxan) work?
- 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
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.