Rifaximin 100mg

Generic For: Xifaxan

Rifaximin 100mg
Rifaximin 100mg — All Family Pharmacy
Rifaximin 100mg — All Family Pharmacy
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Rifaximin (brand name Xifaxan) is a prescription antibiotic that works mainly in the gut with minimal absorption into the bloodstream. It is FDA-approved to treat travelers' diarrhea caused by E. coli, irritable bowel syndrome with diarrhea (IBS-D), and to reduce the risk of hepatic encephalopathy recurrence. After a licensed provider reviews your prescription, your order ships from a licensed U.S. pharmacy.

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Rifaximin is a gut-selective antibiotic used for travelers' diarrhea, IBS with diarrhea (IBS-D), and hepatic encephalopathy.

Medically reviewed by David Paul Mackarey, RPh, Pharmacist-in-Charge

Rifaximin 100mg Quick Facts

Drug classRifamycin antibacterial
TreatsTravelers' diarrhea, IBS-D, hepatic encephalopathy
FormCapsule
Typical dosingTake 1 capsule by mouth up to three times daily as needed for GI symptoms.
Prescription requiredYes — prescription only

What Is Rifaximin 100mg?

Rifaximin is an oral antibiotic in the rifamycin class that stays largely within the digestive tract rather than being absorbed into the body. This gut-targeted action makes it useful for conditions driven by intestinal bacteria. It is sold under the brand name Xifaxan and is available only with a prescription. Your provider will determine whether rifaximin and this strength are appropriate for your condition.

What Does Rifaximin 100mg Treat?

Travelers' diarrhea caused by noninvasive strains of E. coli (adults and children 12+)
Irritable bowel syndrome with diarrhea (IBS-D) in adults
Reduction in risk of overt hepatic encephalopathy recurrence in adults

Rifaximin 100mg Dosage

Travelers' diarrhea: 200 mg by mouth 3 times daily for 3 days.
IBS-D: 550 mg by mouth 3 times daily for 14 days.
Hepatic encephalopathy: 550 mg by mouth 2 times daily.

Your prescriber will determine the dose and duration that are right for you. Always follow the directions on your prescription label.

Rifaximin 100mg Side Effects

Common side effects

  • Nausea
  • Headache
  • Dizziness
  • Fatigue
  • Swelling in hands or feet (peripheral edema)
  • Abdominal pain
  • Muscle spasms

Serious side effects

Stop taking this medication and seek medical attention right away if you experience:

  • Severe or persistent diarrhea (possible C. difficile infection)
  • Allergic reaction (rash, swelling, difficulty breathing)
  • Worsening diarrhea with fever or blood in stool
  • Signs of liver problems (yellowing skin or eyes, dark urine)

Warnings & Interactions

Do not use if allergic to rifaximin or other rifamycin antibiotics
Not effective for diarrhea with fever or blood in the stool
C. difficile-associated diarrhea has been reported with antibiotic use
Use caution in severe hepatic impairment (Child-Pugh C)
May interact with cyclosporine and other P-glycoprotein inhibitors
Tell your provider if symptoms worsen or persist beyond 24-48 hours during treatment
Tell your provider if you are pregnant or breastfeeding

Tell your prescriber about all medications, supplements, and health conditions before starting rifaximin 100mg.

Sources & References

  1. DailyMed - Xifaxan (rifaximin)
  2. MedlinePlus - Rifaximin
  3. FDA - Drugs@FDA: Xifaxan

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Frequently Asked Questions

What is rifaximin used for?

Rifaximin is FDA-approved to treat travelers' diarrhea caused by E. coli, irritable bowel syndrome with diarrhea (IBS-D), and to reduce the risk of hepatic encephalopathy recurrence. It works mainly inside the gut and is minimally absorbed into the body.

Is rifaximin the same as Xifaxan?

Yes, Xifaxan is the brand name for rifaximin. Both contain the same active ingredient and are used for the same FDA-approved conditions.

Do I need a prescription for rifaximin?

Yes, rifaximin is a prescription-only medication in the United States. A licensed healthcare provider must review your health information and issue or confirm a valid prescription before it can be dispensed.

How does ordering and shipping work?

After you submit your prescription or complete a provider review, a licensed pharmacist verifies your order. Your medication is then dispensed and shipped from a licensed U.S. pharmacy directly to your address.

How long does rifaximin take to work?

For travelers' diarrhea, symptoms often improve within 24 to 48 hours of starting treatment. If your symptoms worsen or do not improve, contact your provider, as a different treatment may be needed.

Can I take rifaximin if I have a fever or blood in my stool?

No, rifaximin is not effective for diarrhea accompanied by fever or bloody stools. Contact a healthcare provider promptly if you have these symptoms, as they may indicate a more serious infection.

What are the most common side effects of rifaximin?

Common side effects include nausea, headache, dizziness, fatigue, and swelling in the hands or feet. Contact your provider if you develop severe or persistent diarrhea during or after treatment.