Zaxine (Rifaximin) 550mg

Rifamycin

Brand Name Canada: Zaxine
US Equivalent: Xifaxin

CSA NA – FDA Approved – REMS (N) – Can Ship

Rifaximin inhibits bacterial RNA synthesis by binding to bacterial DNA-dependent RNA polymerase.

Officially indicated to treat hepatic encephalopathy, irritable bowel syndrome without constipation, and traveler’s diarrhea.  It is also prescribed off-label for use in clostridioides difficile infection and small intestinal bacterial overgrowth (SIBO).

Use with caution in patients who may have a hypersensitivity reaction to Xifaxan, Zaxine/Rifaxamin.

Prolonged use may result in fungal or bacterial superinfection, including Clostridioides difficile-associated diarrhea (CDAD) and pseudomembranous colitis.

Clostridioides Difficile Infection (Second or Recurrent)
Oral: Take 400mg three times daily for 20 days; administer after taking a 10-day course of vancomycin.

Hepatic Encephalopathy
Oral: Take 400mg three times daily or 550mg twice daily for 5 to 10 days.

Irritable Bowel Syndrome (without constipation)
Oral: Take 550mg three times daily for 14 days.

Small Intestinal Bacterial Overgrowth (SIBO)
Oral: Take 550mg three times daily for 14 days.  For patients with methane-predominant bacterial overgrowth, some experts use rifaximin as part of an appropriate combination regimen.

Travellers Diarrhea
Oral: Take 200mg three times daily for 3 days.  Avoid in patients with fever or bloody diarrhea.

How to Take Rifaximin, Zaxine/Xifaxan: Can be taken with or without food. 

Do Not Take Rifaximin, Zaxine/Xifaxan: Avoid using if you have diarrhea with fever and/or blood in the stool.  You need to consider alternative therapy if symptoms persist or worsen after 1 to 2 days of treatment.  Use with caution in cases with severe hepatic impairment.

Do Not Take the Generic Version of Rifaximin, Zaxine/Xifaxan for SIBO:  Xifaxan/Zaxine is a non-absorbable rifamycin derivative. It is well tolerated and has been demonstrated to be effective in the treatment of SIBO.  Bioavailability studies have shown that the oral absorption is low which is important so that it can act against bacterial synthesis in the small intestine.  A comparison of the generic versus brand name has shown a significantly lower bioavailability for the brand name which is a distinct advantage over its generic counterpart in terms of therapeutic effectiveness.

Frequency of adverse events generally higher following treatment for hepatic encephalopathy. Percentages are presented for cases of hepatic encephalopathy unless otherwise stated.

>10%:

Cardiovascular: Peripheral edema (15%)

Central Nervous System: Dizziness (13%), fatigue (12%)

Hepatic: Ascites (11%)

Gastrointestinal: Nausea (14%; irritable bowel syndrome with diarrhea 2% to 3%)