From the Guidelines
Rifaximin should be prescribed at a dose of 550 mg taken orally three times daily for 14 days for the treatment of irritable bowel syndrome with diarrhea (IBS-D), and this regimen can be repeated up to two times if symptoms recur. This recommendation is based on the most recent guidelines from the American Gastroenterological Association (AGA) [ 1 ]. The AGA suggests retreatment with rifaximin in patients with IBS-D who develop recurrent symptoms after an initial response [ 1 ].
Key Considerations
- Rifaximin is a nonabsorbable, oral antibiotic with a broad spectrum of activity against both gram-negative and gram-positive anaerobic and aerobic bacteria [ 1 ].
- The FDA-approved dosage for IBS-D is 550 mg three times per day for 14 days [ 1 ].
- Patients who experience a recurrence of symptoms can be retreated up to two times with the same dosage regimen [ 1 ].
- It is essential to complete the full course of treatment even if symptoms improve before completion.
Administration and Side Effects
- Rifaximin can be taken with or without food.
- Common side effects include nausea, bloating, and headache.
- Patients should be advised that rifaximin does not treat viral or parasitic infections, and persistent symptoms warrant medical reevaluation.
- Those with severe liver impairment may require dosage adjustments, and the medication should be used cautiously in patients with severe hepatic impairment.
From the FDA Drug Label
The efficacy of XIFAXAN given as 200 mg orally taken three times a day for 3 days was evaluated in 2 randomized, multi‑center, double-blind, placebo-controlled studies in adult subjects with travelers’ diarrhea. An open-label oral contraceptive study was conducted in 39 healthy female subjects to determine if XIFAXAN 550 mg orally administered three times a day for 7 days altered the pharmacokinetics of a single dose of an oral contraceptive containing 0. 025 mg of ethinyl estradiol (EE) and 0. 25 mg norgestimate (NGM).
The recommended dose and frequency of Rifaximin is:
- 200 mg orally taken three times a day for 3 days for travelers’ diarrhea 2
- 550 mg orally administered three times a day for 7 days in the context of an oral contraceptive study 2
From the Research
Rifaximin Dose and Frequency
- The recommended dose and frequency of rifaximin can be found in several studies, including 3, which states that adults with irritable bowel syndrome with diarrhea (IBS-D) received a 2-week course of rifaximin 550 mg three times a day (TID).
- Another study, 4, mentions that rifaximin is a broad-spectrum oral antibiotic, but does not specify the exact dose and frequency.
- Study 5 discusses the use of rifaximin for the treatment of diarrhea-predominant irritable bowel syndrome, but also does not provide specific information on the dose and frequency.
- However, study 6 provides information on the dosing recommendations of rifaximin for the treatment of travelers' diarrhea, stating that it is approved for patients ≥12 years of age with diarrhea caused by noninvasive strains of Escherichia coli, but does not specify the exact dose and frequency for IBS-D.
Specific Dosing Information
- According to 3, the specific dose and frequency for IBS-D is 550 mg TID for a 2-week course.
- It is essential to consult the prescribing information or a healthcare professional for the most up-to-date and accurate information on rifaximin dosing and frequency for specific conditions.