From the Guidelines
The recommended dose and frequency of Rifaximin for the treatment of Irritable Bowel Syndrome with Diarrhea (IBS-D) is 550 mg three times a day for 14 days.
Key Points
- This dosage regimen is FDA-approved for the treatment of IBS-D 1.
- Patients who experience a recurrence of symptoms can be retreated up to 2 times with the same dosage regimen 1.
- The efficacy of rifaximin in IBS-D has been tested in several randomized controlled trials (RCTs), which have shown that it is more efficacious than placebo for the FDA composite end point for IBS-D and for stool consistency alone 1.
- Rifaximin is a non-absorbable antibiotic with a broad spectrum of activity against both gram-negative and gram-positive anaerobic and aerobic bacteria 1.
- The recommended dose and frequency of Rifaximin may vary depending on the specific clinical context and patient population, but 550 mg three times a day for 14 days is the established dosage regimen for IBS-D 1.
Additional Considerations
- Rifaximin has also been used off-label for the treatment of other conditions, such as hepatic encephalopathy, at a dose of 400 mg three times a day or 550 mg twice a day 1.
- However, the use of rifaximin for these conditions is not FDA-approved, and the dosage regimen may vary depending on the specific clinical context and patient population.
- It is essential to follow the established dosage regimen and to monitor patients for potential adverse events, such as Clostridium difficile infection and bacterial resistance, when using rifaximin for the treatment of IBS-D 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Recommended Dose and Frequency of Rifaximin
The recommended dose and frequency of Rifaximin vary depending on the specific condition being treated.
- For the prevention of recurrent hepatic encephalopathy, a dose of 550 mg twice daily has been shown to be effective 2, 3.
- A study comparing once a day rifaximin to twice a day dosage found no significant difference in preventing hepatic encephalopathy in patients with chronic liver disease 4.
- For the treatment of irritable bowel syndrome, a dose of 1650 mg per day for 2 weeks has been used 5.
- For the treatment of hepatic encephalopathy, doses of 600,1200, and 2400 mg per day have been studied, with the highest dose showing a trend towards a greater treatment effect 6.
Safety and Tolerability
Rifaximin has been shown to be safe and well tolerated for long-term maintenance of remission from overt hepatic encephalopathy, with a median exposure of 427 days and no increase in the rate of infections or development of bacterial antibiotic resistance 3.
- The most common adverse events reported in clinical trials include ascites, dizziness, fatigue, and peripheral edema 2, as well as abdominal pain, diarrhea, bad taste, headache, and upper respiratory tract infection 2, 5.
- Rifaximin can be an effective option for reduction in the risk of the recurrence of hepatic encephalopathy in patients with advanced liver disease, and provides relief of global symptoms of diarrhea-predominant irritable bowel syndrome and bloating 2, 5.