Rankings / Immune & Inflammation

Rifaximin (Xifaxan)

Immune & Inflammation · Gut-selective antibiotic

Tier A+

Reviewed by Read Off Label · Last reviewed · How we grade

prescription
8.4 / 10
Tier A+
Ev 8 Bn 8 Sf 9

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+.

Typical use: 550 mg PO 3x/day for 14 days (IBS-D); 1100 mg 2x/day (hepatic encephalopathy) — Rx.

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

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Common questions

Does Rifaximin (Xifaxan) work?
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+.
Is Rifaximin (Xifaxan) safe?
Rifaximin (Xifaxan) has a low risk profile in published human data. Legal status: Rx. This is not medical advice — see the disclaimer.
What is the typical dose for Rifaximin (Xifaxan)?
550 mg PO 3x/day for 14 days (IBS-D); 1100 mg 2x/day (hepatic encephalopathy)
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.