Xifaxan vs Viberzi

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For patients dealing with irritable bowel syndrome (IBS) or other types of gastrointestinal disorders, certain drugs that alter the balance and activity of bacteria in the gut can help manage symptoms and improve quality of life. Xifaxan and Viberzi are two such drugs commonly prescribed for these conditions. They each impact different aspects within your digestive system but both have effects aimed at reducing IBS-related discomforts.

Xifaxan is an antibiotic, which works by changing the bacterial environment in the intestines to assist in decreasing diarrhea-predominant IBS symptoms. On the contrary, Viberzi is a mu-opioid receptor agonist that slows down intestinal transit time, increases fluid absorption back into your body from your gut and decreases sensitivity to abdominal pain primarily affecting visceral sensation thresholds.

What is Xifaxan?

Rifaximin (the generic name for Xifaxan) is an antibiotic that fights bacterial infections only in the intestines. It was first approved by the FDA in 2004 and it works differently than many antibiotics because it passes through your stomach and into your intestines without being absorbed into your blood stream. This localized activity provides targeted treatment for gastrointestinal disorders like irritable bowel syndrome with diarrhea (IBS-D).

On the other hand, Eluxadoline (the generic name for Viberzi), which was approved by the FDA in 2015, is not an antibiotic but a mu-opioid receptor agonist that slows intestinal motility, decreasing symptoms of IBS-D such as discomfort and diarrhea. Unlike Xifaxan, Viberzi does have effects on opioid receptors throughout the body leading to potential side effects such as constipation or even dependency if misused.

Choosing between these two medications would depend largely on individual patient factors including severity of symptoms, risk of side effects or complications from either drug, and personal preference.

What conditions is Xifaxan approved to treat?

Xifaxan and Viberzi are approved for the treatment of different variations of irritable bowel syndrome:

  • Xifaxan is primarily used to treat diarrhea-predominant irritable bowel syndrome (IBS-D) in adults. It can also be prescribed for hepatic encephalopathy, a condition that affects individuals with severe liver disease.
  • Viberzi, on the other hand, is specifically designed for managing IBS-D in adult men and women by decreasing the contraction of muscles in your gut, thereby reducing instances of diarrhea and abdominal pain.

How does Xifaxan help with these illnesses?

Xifaxan helps manage symptoms of irritable bowel syndrome, particularly in cases where diarrhea is the primary issue. It does this by acting as an antibiotic that stays primarily within the gut and directly targets pathogenic bacteria causing the imbalance in your digestive system. This bacterial overgrowth can lead to bloating, abdominal pain, and frequent irregular bowel movements which are characteristic symptoms of IBS-D (Irritable Bowel Syndrome with Diarrhea). Xifaxan works by inhibiting bacterial RNA synthesis leading to a bactericidal effect on susceptible organisms within the intestine, thus reducing these disruptive effects and helping patients manage their condition more effectively.

On the other hand, Viberzi works differently - it binds to opioid receptors in your intestines, slowing down contractions of your intestinal muscles. This reduction can help control bouts of diarrhea without constipating side effects often seen with other opioids. Additionally, due to its action on certain receptors known as kappa-opioid receptors located throughout our gut wall layers; Viberzi also seems effective at reducing abdominal pain associated with IBS-D.

What is Viberzi?

Viberzi, the brand name for eluxadoline, is a mixed opioid receptor agonist and antagonist that works locally in the gut to reduce visceral hypersensitivity and motility, both of which contribute to symptoms of Irritable Bowel Syndrome with Diarrhea (IBS-D). Unlike Xifaxan, an antibiotic that changes your gut microbiota to manage IBS-D symptoms, Viberzi directly interacts with opioid receptors in your gastrointestinal tract. Approved by the FDA in 2015 as a novel treatment for IBS-D, Viberzi does not majorly affect serotonin levels thus it might be less likely to cause side effects like mood swings or disturbances (often associated with alterations in serotonin levels). This unique mechanism makes Viberzi beneficial especially for patients who don't respond well or cannot tolerate other treatments such as antibiotics like Xifaxan. Nevertheless, due its interaction with opioid receptors it can potentially cause constipation and abdominal pain; these are common side effects quite different from those observed with treatments like Xifaxan.

What conditions is Viberzi approved to treat?

Viberzi is an FDA-approved medication for the treatment of:

  • Irritable bowel syndrome with diarrhea (IBS-D) in adults This emphasizes its use in managing abdominal pain and improving stool consistency in those suffering from IBS-D.

How does Viberzi help with these illnesses?

Viberzi, like Xifaxan, is intended to treat irritable bowel syndrome with diarrhea (IBS-D). However, Viberzi works differently by acting on the mu-opioid receptors in the gut. This reduces gut movement and secretion, thereby reducing diarrhea and abdominal pain. The dual action of Viberzi not only slows down the passage of stool but also decreases the severity of spasms in your gut - a common issue for those suffering from IBS-D. It's particularly beneficial for patients who experience severe symptoms or do not respond well to other treatments such as Xifaxan that primarily work by changing the bacterial population within the intestines.

How effective are both Xifaxan and Viberzi?

Both rifaximin (Xifaxan) and eluxadoline (Viberzi) have been proven effective in treating patients with irritable bowel syndrome with diarrhea, or IBS-D. They were approved by the FDA within a decade of each other; Xifaxan in 2004 and Viberzi in 2015. Since they act on different aspects of the condition, they may be prescribed under varying circumstances.

The effectiveness of Xifaxan and Viberzi for managing symptoms of IBS-D was directly studied in different clinical trials. Both drugs exhibited similar efficacy levels when it comes to reducing abdominal pain and improving stool consistency, along with favorable safety profiles.

A systematic review conducted in 2017 demonstrated that Xifaxan is effective at providing relief from global IBS symptoms as well as bloating starting from the first week of treatment. Its side effect profile showed no major concerns compared to placebo groups, making it a well-tolerated option even for long-term use.

A meta-analysis conducted in 2020 indicated that Viberzi seems more efficacious than placebo for both short term and long term management of IBS-D symptoms like abdominal pain and loose stools. Despite this, there are certain restrictions regarding its prescription due to potential serious adverse effects such as pancreatitis particularly among those who lack a gallbladder.

Given their individual pharmacology, while Xifaxan could be preferred due to fewer significant side-effects especially among patients without a gallbladder or prone to constipation; Viberzi may offer rapid symptom control ideal for those seeking immediate relief.

abstract image of a researcher studying a bottle of drug.

At what dose is Xifaxan typically prescribed?

Oral dosages of Xifaxan range from 200–400 mg three times a day, but research indicates that 200 mg taken three times a day can be effective in treating travelers' diarrhea caused by noninvasive strains of E. coli. For the treatment of irritable bowel syndrome with diarrhea (IBS-D), adults should take one tablet of Viberzi twice daily with food. Both medications have different mechanisms of action and are used to manage different symptoms, so dosage adjustments must always be guided by a healthcare provider's discretion. In any case, the maximum dosage for Xifaxan is 1200 mg/day while for Viberzi it is two tablets per day.

At what dose is Viberzi typically prescribed?

Viberzi treatment typically commences at a dosage of 75-100 mg, taken orally twice daily with food. This means the dose is spread out over approximately 12 hours apart. Should there be no significant improvement in symptoms after some weeks, this can be increased to a maximum dosage of 200mg/day divided into two doses. Each dose would then consist of 100 mg and these should also be spaced roughly 12 hours apart. As always, patients are reminded that adjustments or changes to their prescribed regimen should only occur under direct medical supervision.

What are the most common side effects for Xifaxan?

Common side effects of Xifaxan may include:

  • Nausea
  • Vomiting
  • Constipation
  • Bloating, gas, stomach pain
  • Feeling like you need to urgently empty your bowel
  • Feeling your bowel is not completely empty

While potential side effects for Viberzi can include:

  • Constipation (often severe)
  • Stomach pain and cramps
  • Nausea or vomiting
  • Gas and bloating

It's crucial that any persistent or worsening symptoms are discussed with a healthcare provider as soon as possible.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Xifaxan?

While Xifaxan and Viberzi are both prescribed for irritable bowel syndrome (IBS), they may have different side effects. For Xifaxan, rare but serious side effects include:

  • Severe allergic reactions: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
  • Rapid heartbeat or palpitations
  • Lightheadedness and fainting
  • Liver problems: nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools or jaundice.

On the other hand with Viberzi:

  • Severe constipation that could lead to hospitalization
  • Feeling like you might pass out due to severe abdominal pain and/or pancreatitis symptoms like severe stomach pain that can spread to your back along with nausea and vomiting.

In either case if any of these side-effects occur patients should seek immediate medical attention. Always consult a healthcare provider before starting new medication to discuss possible interactions with existing medications or conditions.

What are the most common side effects for Viberzi?

While taking Viberzi, you may experience the following side effects:

  • Dry mouth or throat
  • Nausea, vomiting, stomach pain, constipation or loss of appetite
  • Sleep issues such as insomnia
  • A fast heartbeat
  • Feelings of anxiety or nervousness
  • Rash development
  • Changes in weight
  • Increased frequency of urination
  • Headaches and dizziness In some cases, patients might also report experiencing muscle or joint pain. Always discuss any potential side effects with your healthcare provider to ensure that Viberzi is the right choice for managing your symptoms effectively.

Are there any potential serious side effects for Viberzi?

While Viberzi is generally well-tolerated, it's crucial to be aware of potential serious side effects including:

  • Signs of an allergic reaction such as hives, itching, difficulty breathing or swallowing; swelling in your face, lips, tongue or throat
  • Severe constipation and stomach pain that could indicate a blockage in the intestines
  • Pancreatitis symptoms: severe upper stomach pain spreading to your back; nausea/vomiting after meals; loss of appetite; rapid weight loss
  • Liver issues characterized by fatigue, weakness, lack of energy or appetite due to reduced liver function (more common if you don't have a gallbladder)
  • Mood changes like depression and suicidal thoughts

If any of these symptoms occur while taking Viberzi, seek immediate medical attention.

Contraindications for Xifaxan and Viberzi?

Both Xifaxan and Viberzi, like most other medications for irritable bowel syndrome (IBS), may worsen symptoms in some individuals. If you notice increased abdominal pain, changes in stool frequency or consistency, weight loss, blood in the stools, or any other alarming symptoms while on these drugs please seek immediate medical attention.

Neither Xifaxan nor Viberzi should be taken if you are taking certain types of medicine. Always inform your physician about your current medication regimen; specifically with Viberzi it is contraindicated if one has a history of biliary duct obstruction, pancreatitis or severe liver impairment. It's also important to note that both Xifaxan and Viberzi require special precaution when co-administered with drugs metabolized by CYP3A4 enzyme system as they could potentially lead to harmful drug-drug interactions.

How much do Xifaxan and Viberzi cost?

For the brand-name versions of these drugs:

  • The price of 60 tablets (550 mg each) of Xifaxan averages around $2,250 which works out to about $75 per day.
  • The price for a month’s supply (60 tablets) of Viberzi (100mg each) is approximately $1,400, working out to roughly $47/day.

Thus, if you are taking the same dosage range for both medications (i.e., two doses per day), then brand-name Viberzi is less expensive on a per-day treatment basis. However, cost should not be your primary consideration in determining which drug is right for you. Your medical condition and how well the medication works for you should be your main considerations.

Currently there are no generic versions available in U.S markets for either Xifaxan or Viberzi as their patents have not expired yet. Therefore one cannot expect significantly lower costs with generic options at this time.

Popularity of Xifaxan and Viberzi

Rifaximin, available as the brand name Xifaxan, was estimated to have been prescribed to about 1.5 million people in the US in 2020. Rifaximin accounted for nearly 30% of prescriptions for antibiotic treatment against irritable bowel syndrome with diarrhea (IBS-D). It appears to be a popular choice due to its minimal systemic absorption and low risk of bacterial resistance.

Eluxadoline, commonly known by its brand name Viberzi, was prescribed around 750 thousand times within the same timeframe within the USA. In terms of IBS-D specific medications, eluxadoline accounts for just under 15% of all prescriptions. Although it has not been on the market as long as rifaximin (Xifaxan), eluxadoline's prevalence has been generally increasing since its approval by FDA in 2015 thanks to its dual action mechanism which helps regulate bowel contractions while reducing pain.


Both Xifaxan (rifaximin) and Viberzi (eluxadoline) have proven effective in managing symptoms of irritable bowel syndrome with diarrhea (IBS-D). They are supported by multiple clinical studies that demonstrate their efficacy compared to placebo treatments. The two drugs operate through different mechanisms of action, with Xifaxan being an antibiotic that alters gut bacteria, while Viberzi is a mixed opioid receptor agonist/antagonist affecting gut motility and visceral sensitivity.

Xifaxan is usually considered as the first line treatment for IBS-D due to its fewer side effects. However, it may require repeat courses of therapy if symptoms recur after initial improvement. On the other hand, Viberzi would typically be prescribed when patients do not respond well to non-opioid medications or have severe cases of IBS-D needing immediate symptom relief.

Both medications are available in generic form which can lead to significant cost savings for patients who must pay out-of-pocket. Both Xifaxan and Viberzi may also necessitate some time before the therapeutic effects become evident.

As far as safety is concerned, both drugs generally exhibit good tolerability although there's potential for certain adverse reactions. For instance, Xifaxan might cause mild gastrointestinal side-effects whereas Viberzi could potentially cause serious outcomes such as pancreatitis or sphincter of Oddi spasm especially in those without a gallbladder so caution should be taken when prescribing this drug. Patients should report any unusual abdominal pain or discomfort experienced during treatment immediately to their healthcare provider.