Amitiza vs. Linzess: Understanding the Differences

Amitiza vs. Linzess: Understanding the Differences

Authored by The Rx Advocates, / Medically Reviewed by Dr. Conor Sheehy, PharmD, BCPS
Last Updated: September 22, 2023


Amitiza and Linzess are two commonly prescribed medications used to treat chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C). These conditions are characterized by persistent constipation and abdominal discomfort.

Amitiza contains lubiprostone and increases fluid secretion in the intestines to promote bowel movements. Linzess contains linaclotide and acts on specific receptors in the gut to enhance bowel motility and reduce pain associated with constipation.

Both medications help relieve the symptoms of these gastrointestinal disorders and improve the regularity of bowel movements as a part of a chronic constipation treatment.

Understanding the differences and similarities between Amitiza and Linzess will enable patients to make choices that align with their unique needs and preferences, ultimately improving their quality of life.

Through a comprehensive analysis, individuals and their healthcare providers can make informed decisions about which medication may be the most suitable option for managing their gastrointestinal condition. This gastrointestinal medications comparison examines the mechanisms of action, efficacy, potential adverse effects, and other relevant factors.

Mechanism of action for Amitiza and Linzess


Amitiza’s mechanism of action involves targeting chloride channels in the intestinal lining.

Specifically, it contains the active ingredient lubiprostone, which activates CIC-2 chloride channels in the small intestine. This activation increases chloride-rich fluid secretion into the intestines, softening stool and promoting bowel movements.

Additionally, Amitiza (the lubiprostone brand name) may enhance gut motility and reduce visceral pain sensitivity, contributing to its effectiveness in treating chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C). This unique mechanism makes Amitiza a valuable option for individuals seeking relief from these gastrointestinal conditions.


Linzess operates through the activation of guanylate cyclase-C (GC-C) receptors in the lining of the intestinal tract.

It contains linaclotide, a synthetic peptide, which binds to these receptors, increasing cyclic guanosine monophosphate (cGMP) levels. Elevated cGMP levels result in enhanced fluid secretion into the intestines and reduced pain sensitivity, softening stool, increasing bowel movements, and alleviating abdominal discomfort.

By specifically targeting the GC-C receptors, Linzess offers a targeted approach to addressing the symptoms of CIC and IBS-C, making it an effective FDA-approved IBS medication choice for treating these conditions.

Differences and similarities

Though both are used to act as bowel movement regulators, Linzess vs. Amitiza have differences as well as similarities in their mechanisms of action.

Differences: Amitiza contains lubiprostone, and Linzess contains linaclotide. Amitiza activates chloride channels in the intestine, while Linzess stimulates guanylate cyclase-C receptors, leading to elevated cGMP levels and reduced pain sensitivity.

Similarities: Both medications increase intestinal fluid secretion and promote bowel movements.

Both medications enhance fluid in the intestines but their specific targets and pathways vary. These differences may influence individual treatment preferences, but they share the common goal of relieving constipation and associated discomfort.

Efficacy of Lubiprostone vs. Linaclotide

Considering the effectiveness of lubiprostone vs linaclotide (the active ingredients in Amitiza and Linzess, respectively) is a proactive way to consider which medication is best for you.


Several studies have examined the effectiveness of Amitiza (or its generic form of lubiprostone) in treating CIC and IBS-C.

Clinical trials have consistently shown that Amitiza significantly improves bowel movement frequency and stool consistency compared to a placebo. Moreover, it has demonstrated efficacy in reducing abdominal discomfort and pain associated with constipation.

These findings indicate that Amitiza is a valuable treatment option for individuals with these conditions, helping to alleviate symptoms and improve overall quality of life.


Numerous clinical studies have investigated the effectiveness of Linzess (linaclotide) in managing these chronic gastrointestinal conditions.

These studies consistently reveal that when Linzess is compared to placebo, patients experience significant improvements in bowel movement frequency, stool consistency, and overall relief from constipation symptoms . Linzess has also demonstrated efficacy in reducing abdominal pain and discomfort, key symptoms of IBS-C.

These findings support Linzess as an effective and well-tolerated treatment option for individuals dealing with CIC and IBS-C.

Comparison of Linzess vs. Amitiza

Amitiza and Linzess are both effective in treating CIC and IBS-C. However, there are some differences in patients’ experiences between the two drugs. Note that the drugs have not been directly compared to one another.

Onset of Action:

    • Amitiza typically has a faster onset of action, with some individuals experiencing relief within 24 hours of taking the medication.
    • Linzess may take a few days to a week to reach its full effectiveness.

Bowel Movement Frequency:

    • Amitiza has been shown to increase bowel movement frequency in clinical trials.
    • Linzess also increases bowel movements but may have a slightly more pronounced effect on stool frequency for some individuals.

Stool Consistency:

    • Both medications improve stool consistency, making stools softer and easier to pass.

Abdominal Discomfort:

    • Amitiza and Linzess have demonstrated efficacy in reducing abdominal discomfort and pain associated with constipation, with some variations in individual responses.

Overall Efficacy:

    • Overall, the efficacy of Amitiza and Linzess is relatively similar, and both can provide significant relief from CIC and IBS-C symptoms.

Dosage and administration of Amitiza and Linzess

Consider the following dosage guidelines for these IBS-C medications and their generic alternatives.

Amitiza dosage

The typical dosage and administration of Amitiza is as follows:

  • For adults, the initial recommended dose is 24 micrograms (mcg) taken orally twice daily with food.
  • For irritable bowel syndrome with constipation (IBS-C), the initial recommended dose is 8 mcg taken orally twice daily with food.
  • Depending on individual response, the healthcare provider may adjust the dosage.
  • Amitiza should be taken with food and water to optimize its effectiveness in relieving constipation symptoms.

Linzess dosage

The typical dosage and administration of Linzess are as follows:

  • For CIC in adults, the recommended starting dose is 145 mcg once daily, taken on an empty stomach at least 30 minutes before the first meal of the day.
  • For IBS-C in adults, the recommended starting dose is 290 mcg once daily on an empty stomach.
  • Healthcare providers may adjust the dose based on individual patient responses.
  • Patients should adhere to their healthcare provider’s prescribed dosing instructions for optimal results.

Which is better?

One advantage of Amitiza is its relatively fast onset of action, providing quick relief for some individuals.

On the other hand, Linzess is administered as a once-daily dose, which may improve adherence for some patients. However, it may take longer to reach its full effectiveness.

So, how is Linzess different from Amitiza? The choice between the two medications often depends on individual preferences, tolerability, and the patient’s specific needs.

Adverse effects of Amitiza and Linzess


Commonly reported adverse effects of Amitiza (lubiprostone) include gastrointestinal symptoms such as nausea, diarrhea, abdominal pain, and flatulence. These reactions are usually mild to moderate in severity and tend to occur early in treatment.

Nausea is one of the most frequently reported adverse effects. However, these symptoms often diminish as the body adjusts to the medication.


Commonly reported adverse effects of Linzess (linaclotide) include gastrointestinal symptoms such as diarrhea, abdominal pain, and flatulence. Diarrhea is the most frequently reported reaction and may be bothersome for some individuals. Abdominal pain is also common but is often described as mild to moderate in severity. These adverse reactions typically occur within the first few weeks of treatment and tend to diminish over time.

Comparison of adverse effects between Linzess vs. Amitiza

Both Linzess and Amitiza are effective treatments for chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C). Still, their side effects differ.

Amitiza’s common negative reactions include nausea, diarrhea, abdominal pain, and flatulence. These adverse effects are generally mild to moderate and tend to improve with continued use.

In contrast, Linzess commonly causes diarrhea and abdominal pain, with diarrhea being the most frequent adverse effect. While these are generally mild to moderate and can improve over time, they may be more pronounced for some individuals.

Unique to Amitiza, some individuals may experience flatulence, which is less commonly reported with Linzess. However, Linzess is administered once daily, which may improve overall treatment adherence.

Ultimately, the choice between the two medications may depend on individual tolerability and the specific negative reactions experienced. Patients must discuss their preferences and responses (including any persistent or severe side effects) with their healthcare provider to determine the best course of action and ensure a safe and effective treatment experience.

Interactions for Amitiza vs. Linzess


Amitiza is generally considered safe and is a known Linzess alternative. However, there are some known significant interactions:

  • Alcohol: Excessive alcohol consumption can increase the risk of negative effects like dizziness when taken with Amitiza.


Linzess is generally considered safe when used as directed, with some known significant interactions:

  • Antidiarrheal Medications: Combining Linzess with antidiarrheal drugs can counteract its effectiveness.
  • Digestive System Motility Agents: Other medications that affect gut motility, such as prucalopride, might interact with Linzess, potentially leading to unpredictable results.

It’s crucial for individuals taking Amitiza and Linzess to inform their healthcare provider about all medications and supplements they are taking to avoid potentially interacting with other medications or sources. Minimizing this risk of interactions when using medications increases the effectiveness of treating the conditions.

Cost and availability

While Amitiza and Linzess generic alternatives do exist, knowing the cost and availability of these medications can increase treatment options.


The typical cost of Amitiza can vary depending on dosage, location, and insurance coverage. However, it’s worth noting that no generic versions of Amitiza are available in the United States.


The typical cost of Linzess could vary significantly based on dosage, location, and insurance coverage.

Prices and generic availability may have changed, so individuals should consult their healthcare provider or pharmacist for current information on cost and potential generic Linzess alternatives.

The Rx Advocates can help you pay for Amitiza or Linzess

Amitiza (lubiprostone) and Linzess (linaclotide) are medications used to treat chronic constipation conditions. They share the same therapeutic goals and can cause similar adverse effects. Patient reviews and experiences can help you determine if these medications are right for you.

However, each has different dosages, mechanisms of action, and interactions. These factors and others affect their respective costs and availability.

The Rx Advocates will work with you, based on your eligibility, to ensure you have the medication you need to live the healthy life you deserve. If you need assistance in paying for your prescription, contact us today.

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  2. NCBI. Linaclotide: Mechanism of Action. April 25, 2023. Available at:
  3. NIH. Amitiza efficacy. December 7, 2022. Available at:
  4. NIH. Linzess efficacy. March 2013. Available at:
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  6. Medical News Today. Linzess: Dosage. April 14, 2022. Available at:
  7. MedlinePlus. Lubiprostone: Side Effects. July 2017. Available at:
  8. MedlinePlus. Linaclotide: Side Effects. August 15, 2023. Available at:
  9. Medical News Today. Amitiza: Interactions. September 2, 2022. Available at:
  10. Medical News Today. Linzess: Interactions. April 14, 2022. Available at:
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