Generic Rifaximin

Common use

Rifaximin is a broad-spectrum antibiotic used to treat traveler’s diarrhea caused by certain bacteria, as well as irritable bowel syndrome with diarrhea (IBS-D) and hepatic encephalopathy in adults. It works by stopping the growth of bacteria in the intestines without being absorbed significantly into the bloodstream. Rifaximin is effective mainly in the gastrointestinal tract. It helps reduce symptoms like bloating, gas, and loose stools.

Dosage and direction

Rifaximin is usually taken by mouth, with or without food, as directed by your doctor. The dosage and duration depend on the condition being treated — commonly taken for 3 to 14 days. It is important to complete the full course even if symptoms improve early. Swallow the tablets whole with water and take them at the same times each day for best results.

Precautions

Before using rifaximin, tell your doctor if you have liver disease, a history of allergic reactions to rifamycin antibiotics, or if your symptoms worsen or do not improve. Though side effects are uncommon, prolonged use may lead to overgrowth of non-susceptible organisms. This medication should not be used to treat infections caused by viruses such as the common cold or flu. Avoid taking it for longer than prescribed.

Contraindications

Rifaximin is contraindicated in patients with known hypersensitivity to rifaximin or any of its components. It should not be used in cases where the cause of diarrhea is not bacterial, such as in viral gastroenteritis. Patients with severe liver impairment may need close monitoring or dose adjustment. Consult your doctor before starting if you are pregnant or breastfeeding.

Possible side effect

Common side effects include nausea, bloating, headache, and abdominal pain. In some cases, users may experience dizziness, fatigue, or increased liver enzymes. Rare but serious reactions can include allergic reactions such as rash, itching, or swelling. Seek immediate medical attention if you notice signs of an allergic response or worsening symptoms.

Drug interaction

Rifaximin has a low risk of systemic interactions due to minimal absorption into the bloodstream. However, it may still interact with drugs that affect liver enzymes, including cyclosporine. Always inform your healthcare provider of all prescription and non-prescription medications and supplements you are taking. No significant food interactions are known, but follow your doctor’s advice.

Missed dose

If you miss a dose, take it as soon as you remember. If it’s almost time for the next dose, skip the missed one and continue with your regular schedule. Do not double the dose to catch up. Staying consistent helps the medication work more effectively.

Overdose

Overdose with rifaximin is rare due to its low absorption, but taking excessive doses can lead to increased side effects such as stomach upset or allergic reactions. In case of suspected overdose, seek immediate medical help. Supportive treatment is usually sufficient. Always follow dosing instructions carefully.

Storage

Store rifaximin tablets at room temperature away from moisture and heat. Keep the medication in its original container and out of reach of children and pets. Do not use after the expiration date. Dispose of unused medicine according to local regulations or your pharmacist’s instructions.

Disclaimer
We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)