What is rifaximin?

Rifaximin is a drug classified as an active ingredient by medicine, belonging to the line of broad-spectrum antibiotic drugs, with an effect on some bacteria that cause infections in the body. (1)

What is rifaximin used for?

  • Thanks to its mechanism of action, rifaximin inhibits bacterial RNA and protein synthesis , thus achieving a bactericidal effect against susceptible bacteria. Consequently, it mitigates the infection caused by pathogenic microorganisms and their annoying symptoms.
  • It is used to treat:
    • Irritable bowel syndrome. (two)
    • Bacterial overgrowth of the small intestine.
    • Secondary hyperammonemia and liver failure as an adjuvant. (3)
    • Symptomatic diverticular disease of the colon.
    • Infectious complications in surgery of the gastrointestinal tract.
    • Acute and chronic intestinal infections, diarrheal syndrome.
    • The alteration in the balance of the normal intestinal flora, such as traveler’s diarrhea or enterocolitis.
    • Vancomycin -resistant pseudomembranous colitis.
    • Diarrhea caused by the bacteria Escherichia coli .
    • Bacterial enterocolitis in patients at risk due to associated pathology or immunosuppression.

Dosage and routes of administration of rifaximin

The presentation of rifaximin is in tablets, which may contain rifaximin of 200 mg, 400 mg or 550 mg depending on the manufacturing laboratory. The administration is orally and the posology as a reference, can be the following:

  • Infectious diarrhea: Children 6 to 12 years of age, 1 to 2 tablets of 200 to 400 mg every 12 hours. Children over 12 years of age and adults, one 200 mg tablet three times a day.
  • Irritable Bowel Syndrome: Children over 12 years of age and adults, two 200 mg tablets or one 400 mg or one 550 mg tablet three times a day are recommended.

What products contain rifaximin?

Some of the medicines that contain rifaximin are:

  • Flonorm®
  • Arfla®
  • Rixim®
  • Normix®


  • Flonorm® is a semi-synthetic antibiotic drug that uses rifaximin as the active ingredient.
  • It is used to treat diarrhea due to various aetiologies .
  • For more information about this medicine, see What is flonorm and what is it used for? .


  • Arfla® is a semi-synthetic drug with a broad-spectrum antibiotic effect, which uses rifaximin as its active ingredient.
  • It is indicated in the treatment of irritable bowel syndrome and some bacterial infections in the gastrointestinal tract.


  • Rixim® is the registered trademark of a drug, which contains rifaximin as an active ingredient and is presented in the form of tablets.
  • It is indicated in the treatment of diarrhea caused by bacterial infection in the digestive tract.


  • Normix® is a broad-spectrum bactericidal antibiotic that contains rifaximin as an active ingredient.
  • It is indicated mainly to treat traveler’s diarrhea .

Rifaximin Side Effects

Therapeutic treatment with rifaximin may cause some of the following adverse reactions in a certain patient population:

  • Possible allergic reactions due to patient contact with any component of the formula.
  • Nausea, dyspepsia, vomiting and urticaria.
  • Abdominal pain and rectal tenesmus .

Important: If during treatment with this drug the patient shows any of these symptoms or other side effects not included in the list, please discontinue use and inform your doctor .

Contraindications and warnings of rifaximin

The use of rifaximin is contraindicated in the following cases:

  • Patient hypersensitivity to the components of the formula.
  • Patients with severe ulcerative lesions of the intestine.
  • During the pregnancy period.
  • During breastfeeding .

To emphasize: Provide all the information regarding your health history to your doctor, before starting treatment with this drug.

Avoid it if you have:

  • History of hypersensitivity to any component of the formula or to rifamycins.
  • Diarrhea and fever or presence of blood in the stool .


  • Pharmaceutical products such as rifaximin must be administered with a prescription or prescription.
  • Do not alter the dose indicated by the doctor and follow his instructions.
  • The administration of this medicine must be supervised by a doctor.
  • Long-term use of antibiotics can create resistant organisms.
  • Keep this medicine out of the reach of children.
  • Store in a cool dry place.

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