Select a medication above to begin.
Xifaxan
rifaximin
Adult Dosing .
Dosage forms: TAB: 200 mg, 550 mg
traveler's diarrhea, E. coli-induced
- [200 mg PO tid x3 days]
hepatic encephalopathy
- [550 mg PO bid]
IBS, diarrhea-predominant
- [550 mg PO tid x14 days]
- Info: may repeat dose up to 2x if recurrent dz
recurrent C. difficile infection, adjunct (off-label)
- [400 mg PO tid x20 days]
- Info: for 2 or more recurrences; give after 10 days of vancomycin PO
renal dosing
- [not defined]
- renal impairment: not defined
- HD/PD: not defined
hepatic dosing
- [see below]
- Child-Pugh Class A or B: no adjustment; Child-Pugh Class C: not defined, caution advised
Peds Dosing .
- Dosage forms: TAB: 200 mg
traveler's diarrhea, E. coli-induced
- [12 yo and older]
- Dose: 200 mg PO tid x3 days
recurrent C. difficile infection, adjunct (off-label)
- [3 yo and older]
- Dose: 200 mg PO tid x14 days; Info: for 2 or more recurrences; give after 14 days of vancomycin PO
renal dosing
- [not defined]
- renal impairment: not defined
- HD/PD: not defined
hepatic dosing
- [see below]
- Child-Pugh Class A or B: no adjustment; Child-Pugh Class C: not defined, caution advised
Contraindications / Cautions .
- hypersensitivity to drug or ingredient
- hypersensitivity to rifamycins
- caution: hepatic impairment, Child-Pugh Class C
- caution: abx-associated colitis hx, recent
Drug Interactions .
Overview
rifaximin
rifamycin
- P-gp substrate
- alters GI flora
Avoid/Use Alternative
- fecal microbiota, live
- methotrexate
Monitor/Modify Tx
- vimseltinib
- warfarin
Caution Advised
- belumosudil
- cannabidiol
- cobicistat
- cyclosporine
- dronedarone
- glecaprevir
- itraconazole
- ketoconazole
- lactulose
- levoketoconazole
- pibrentasvir
- propafenone
- quinidine (antiarrhythmic)
- sodium picosulfate
- verapamil
- voxilaprevir
Adverse Reactions .
Serious Reactions
- superinfection
- C. difficile-assoc. diarrhea
- hypersensitivity rxn
- angioedema
- anaphylaxis
- exfoliative dermatitis
- Stevens-Johnson syndrome
- toxic epidermal necrolysis
Common Reactions
- peripheral edema
- nausea
- dizziness
- fatigue
- ascites
- headache
- muscle spasms
- pruritus
- abdominal pain
- anemia
- depression
- nasopharyngitis
- arthralgia
- dyspnea
- fever
- rash
- ALT incr.
Safety/Monitoring .
Monitoring Parameters
no routine tests recommended
Look/Sound-Alike Drug Names
Xifaxan confused with: Reprexain
rifAXIMin confused with: rifAMPin
Pregnancy/Lactation .
Pregnancy
Clinical Summary
weigh risk/benefit during pregnancy; no human data available, though risk of fetal harm not expected based on minimal systemic absorption; possible risk of teratogenicity in 1st trimester based on animal data at up to 33x recommmended human doses
Lactation
Clinical Summary
may use while breastfeeding; no human data available, though risk of infant harm and adverse effects on milk production not expected based on minimal maternal systemic absorption
Pharmacology .
Metabolism: none; CYP450: none; Info: minimal to no systemic absorption
Excretion: feces 97% (primarily unchanged); Half-life: 6h
Subclass: Clostridioides difficile ; Diarrhea ; Hepatobiliary ; Irritable Bowel Syndrome (IBS) ; Rifamycins
Mechanism of Action
inhibits DNA-dependent RNA polymerase
Formulary .
No Formulary Selected
Join Now to View Patient Handouts!
Create a FREE epocrates Online account to access patient medication instructions. Your patients and caregivers will appreciate you printing these friendly handouts, available in English and Spanish. Each handout addresses common concerns such as how to take the medication, and possible side effects.
Current Members: Sign In.
Pill Pictures
Join Now to View Pill Pictures!
Create a FREE epocrates Online account to access full-color images of medications within the drug monograph.
Current Members: Sign In.