Table of Contents

I. Understanding E. Coli Bacteria

II. What is Xifaxan?

III. What are the functions of Xifaxan?

IV. How Quickly Does Xifaxan Work?

V. FAQ: What Should I Do If Xifaxan Doesn't Seem to Be Working?

Understanding E. Coli Bacteria

The E. coli (Escherichia coli) bacteria live in the intestines without causing any health problems. However, certain strains of the E. coli bacteria can cause moderate to severe diarrhea, including symptoms of abdominal cramps, blood in the stool, and vomiting. E.coli can enter the body through contaminated food or water. This commonly occurs when people consume raw vegetables or undercooked meat. After exposure to a harmful strain of E. coli, you may experience symptoms right away or more than a week later. Researchers have found that ETEC (enterotoxigenic E. coli) is the most common bacterial cause of diarrhea symptoms, including travelers' diarrhea. A more severe strain, E. coli O157:H7, is less common but can cause bloody diarrhea and serious complications. Infections with this strain can increase the risk of life-threatening complications, especially in older adults and younger children.

The E. coli bacteria can cause diarrhea because they produce powerful toxins that attack and damage the small intestine's lining. Even in small amounts, E. coli can cause you to fall sick. In addition to older adults and younger children, those with a weakened immune system or decreased stomach acid levels are at higher risk of infection.

To lower the risk of diarrhea from E. coli, limit products made from raw milk, unpasteurized milk, unpasteurized apple juice, and undercooked meats. If you have been infected with E. coli, your doctor may prescribe Xifaxan to relieve diarrhea symptoms. Read on to learn more about Xifaxan and how this medication works. [1]

What is Xifaxan?

Xifaxan is the brand-name drug of rifaximin, an antibiotic that relieves diarrhea symptoms by stopping or slowing the growth of bacteria. In addition to diarrhea, Xifaxan may be prescribed to prevent episodes of hepatic encephalopathy, a condition involving a build-up of toxins in the brain. The dosage for Xifaxan may vary depending on the condition it is intended to treat. Generally, Xifaxan works best when taken at evenly spaced times. Below are some common functions of Xifaxan.

What are the functions of Xifaxan?

a. Traveler's Diarrhea

The symptoms of traveler's diarrhea include stomach cramps, loss of appetite, bloating, and fever. This type of diarrhea is rarely life-threatening, but symptoms can last up to a week. Traveler's diarrhea is most common in developing countries where the food and water supply are more likely to be contaminated by E. coli. You can reduce your risk of traveler's diarrhea when abroad by drinking boiled or bottled water, avoiding raw meats, and avoiding drinks with ice to avoid frozen tap water.

Despite your best preventive efforts, you may still contract an E. coli infection. If you experience symptoms of traveler's diarrhea, you may ask your doctor about Xifaxan. Xifaxan is typically taken orally and once every eight hours for three days. This general guideline is usually effective in reducing traveler's diarrhea symptoms, but you may need to contact a doctor if you have serious symptoms such as bloody diarrhea, fever and chills, or dehydration. [2]

b. IBS with Diarrhea

Irritable bowel syndrome with diarrhea (IBS-D) is a condition that can cause frequent bowel movements, loose stools, stomach pain, and increased diarrhea. IBS-D causes the colon to become more sensitive to bacterial infections. There is no cure for IBS, but combining a treatment plan of Xifaxan with dietary changes can help patients manage symptoms.

For IBS-D, Xifaxan is usually prescribed three times a day for two weeks. Once Xifaxan decreases bacterial growth in the body, diarrhea symptoms should go away. Treatment with Xifaxan can be repeated up to two times if symptoms return. [2]

c. Hepatic Encephalopathy

Hepatic encephalopathy is a nervous system disorder that can occur in patients with severe liver disease. The liver is a key organ that filters toxins from the blood. When the liver is diseased, these toxins can remain in the body and build up in the bloodstream.

If these toxins travel to the brain, brain function can be affected, resulting in changes to the patient's behavior. Patients with this condition may seem confused at times. Treatment for hepatic encephalopathy typically involves laxatives or antibiotics like Xifaxan.

Because Xifaxan can reduce bacterial growth, this medication can lower the toxin levels in the body. To prevent episodes of hepatic encephalopathy, Xifaxan is typically taken twice a day, generally once every 12 hours.

Sticking to the treatment plan can improve your chance of slowing, stopping, and even reversing this disease. Patients affected by hepatic encephalopathy often need medications to treat their liver disease to prevent this condition from reoccurring. If you have liver disease and notice mood changes, impaired thinking, or sleep problems, speak to your doctor about Xifaxan. [3]

How Quickly Does Xifaxan Work?

The efficacy of Xifaxan depends on the condition you are treating. For traveler's diarrhea, Xifaxan should relieve symptoms within 24 to 48 hours after you start taking this medication. [2] For IBS-D, you may need to complete your two-week course of treatment before benefiting from the full effects of this drug. However, after two weeks of taking Xifaxan, you should be symptom-free for up to 10 weeks. If you experience IBS-D symptoms right after taking rifaximin for two weeks, contact your doctor. [4]

To learn more about how Xifaxan (rifaximin) can help you or what to know before taking Xifaxan, visit Canadian Med Center's blog section for educational resources and research material. If you are ready to fill your prescription for Xifaxan, visit our online ordering portal today. At Canadian Med Center, we offer brand-name Xifaxan and generic rifaximin at several different strengths and prices. Save time and money with our quick ordering, around-the-clock helpline, and delivery.

FAQ: What Should I Do If Xifaxan Doesn't Seem to Be Working?

Xifaxan works within different timeframes depending on the condition being treated, so what counts as "not working" looks different for each. If you're taking Xifaxan for traveler's diarrhea and don't notice improvement within 24 to 48 hours, or if your symptoms include fever, chills, dehydration, or bloody diarrhea, this is not something to wait out on your own. 

These symptoms can indicate a more serious infection that Xifaxan may not be equipped to treat, and your doctor may need to reassess your diagnosis or prescribe a different treatment.

If you're taking Xifaxan for IBS-D, remember that this medication requires a full two-week course before its complete effects can be evaluated. Stopping early because you don't feel better after a few days can prevent the treatment from working as intended and may also contribute to antibiotic resistance. 

If you complete the full two weeks and still don't experience relief, or if your symptoms return sooner than the expected 10-week window, contact your doctor. You may be a candidate for retreatment, since Xifaxan can be repeated up to two times for IBS-D, or your doctor may want to explore other underlying causes.

For hepatic encephalopathy, "not working" can still look different. Because Xifaxan is used to prevent episodes rather than treat sudden symptoms, you may not notice an immediate effect. 

Instead, watch for whether the confusion, mood changes, or impaired thinking associated with hepatic encephalopathy continue to recur despite consistent treatment. This is not a condition to monitor passively, since worsening symptoms can escalate quickly and may require immediate medical attention.

Across all three conditions, do not stop taking Xifaxan, change your dose, or assume it isn't working without first speaking to your doctor. What feels like a treatment failure may actually be a sign that something else is going on, and your doctor is best positioned to make that call.

If you're concerned that Xifaxan isn't working as expected:

1. Confirm you're taking Xifaxan exactly as prescribed, including the correct frequency and full course length.
2. Track when your symptoms started, whether they've improved at all, and how they compare to the expected timeline for your condition.
3. Watch for warning signs that need urgent attention, such as fever, bloody stools, dehydration, or worsening confusion.
4. Do not stop or adjust your dose on your own, even if you feel treatment isn't working.
5. Contact your doctor if symptoms haven't improved within the expected window, or sooner if warning signs develop.
6. Ask your doctor whether retreatment, a different medication, or further testing is the right next step for your specific condition.

The content in this article is intended for informational purposes only. This website does not provide medical advice. In all circumstances, you should always seek the advice of your physician and/or other qualified health professionals(s) for drug, medical condition, or treatment advice. The content provided on this website is not a substitute for professional medical advice, diagnosis, or treatment.