What the label lists and what reports show
Rifaximin side effects
Rifaximin's FDA label: “Most common adverse reactions: • TD (≥2%): Headache ( 6.1 ) • HE (≥10%): Peripheral edema, nausea, constipation, dizziness, fatigue, urinary tract infection, insomnia, anemia, pruritus, and ascites ( 6.1 ) • IBS-D (≥2%): ALT increased, nausea ( 6.1 ) To …” FAERS holds 20,826 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is diarrhoea (1,243 reports).
- No generic listed
Check it at the source: the rifaximin FDA label on DailyMed (effective June 25, 2025, Salix Pharmaceuticals, Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions: • TD (≥2%): Headache ( 6.1 ) • HE (≥10%): Peripheral edema, nausea, constipation, dizziness, fatigue, urinary tract infection, insomnia, anemia, pruritus, and ascites ( 6.1 ) • IBS-D (≥2%): ALT increased, nausea ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
A table the label prints in its adverse reactions section without a title; its column headings name the groups compared
| Adverse Reaction | XIFAXAN Tablets 550 mg TWICE DAILY + Lactulose (N=108) n (%) | XIFAXAN Tablets 550 mg TWICE DAILY (N=113) n (%) |
|---|---|---|
| Peripheral edema | 15 (14%) | 19 (17%) |
| Insomnia | 15 (14%) | 13 (12%) |
| Ascites | 14 (13%) | 8 (7%) |
| Diarrhea | 13 (12%) | 6 (5%) |
| Nausea | 11 (10%) | 17 (15%) |
| Muscle spasms | 11 (10%) | 9 (8%) |
| Dyspnea | 10 (9%) | 8 (7%) |
| Anxiety | 10 (9%) | 6 (5%) |
| Constipation | 9 (8%) | 18 (16%) |
| Fatigue | 9 (8%) | 16 (14%) |
| Urinary tract infection | 9 (8%) | 13 (12%) |
| Abdominal pain | 8 (7%) | 8 (7%) |
| Pruritus | 6 (6%) | 11 (10%) |
| Decreased appetite | 5 (5%) | 8 (7%) |
| Headache | 5 (5%) | 8 (7%) |
| Cough | 5 (5%) | 6 (6%) |
| Renal failure acute | 5 (5%) | 7 (6%) |
| Vomiting | 6 (5%) | 6 (6%) |
| Anemia | 3 (3%) | 11 (10%) |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in labeling: • Clostridium difficile -associated diarrhea [see Warnings and Precautions ( 5.2 )] Most common adverse reactions: • TD (≥2%): Headache ( 6.1 ) • HE (≥10%): Peripheral edema, nausea, constipation, dizziness, fatigue, urinary tract infection, insomnia, anemia, pruritus, and ascites ( 6.1 ) • IBS-D (≥2%): ALT increased, nausea ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Travelers’ Diarrhea The safety of XIFAXAN 200 mg taken three times a day was evaluated in patients with travelers’ diarrhea consisting of 320 patients in two placebo-controlled clinical trials with 95% of patients receiving three or four days of treatment with XIFAXAN. The population studied had a mean age of 31.3 (18-79) years of which approximately 3% were ≥65 years old, 53% were male and 84% were White, 11% were Hispanic. Discontinuations due to adverse reactions occurred in 0.4% of patients. …
Source: FDA drug label, Salix Pharmaceuticals, Inc., effective June 25, 2025 (SPL set c5e8e2fd-7087-4b78-9181-cc259c0be2f1), via openFDA; the full label on DailyMed
What do FAERS reports show?
20,826 reports list rifaximin among the medicines taken, each a report of something that happened, not proof the medicine caused it; 6,105 are coded as a death and 8,176 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 16 reactions below, 6 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Rifaximin: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions