Amitiza (Lubiprostone) - Oral

What Is Amitiza?

Amitiza (lubiprostone) is a prescription laxative medication in the class of drugs known as prostaglandins. The Food and Drug Administration (FDA) approved it to treat constipation from various causes. Lubiprostone works by increasing the amount of fluid in the bowels by boosting chloride production in the intestine. This softens the stool, allowing it to pass more easily.

Amitiza is available as an oral soft gel capsule in strengths of 8 micrograms (mcg) and 24 mcg.

Drug Facts

Generic Name: Lubiprostone

Brand Name(s): Amitiza

Drug Availability: Prescription

Therapeutic Classification: Laxative

Available Generically: Yes

Controlled Substance: N/A

Administration Route: Oral

Active Ingredient: Lubiprostone

Dosage Form: Capsule

What Is Amitiza Used For?

The FDA approved lubiprostone to treat adults with:

  • Chronic or long-term constipation from unknown causes: difficult or infrequent stools that lasts for three months or longer. This type of constipation is not linked to a disease or any medication.
  • Constipation caused by opioid (narcotic) pain medicine
  • Irritable bowel syndrome with constipation as the main symptom (in women only)

Verywell / Dennis Madamba

How to Take Amitiza

Use this medicine exactly as directed by your healthcare provider. Follow all directions on your prescription label, and ask your pharmacist for any clarification you might need.

Take lubiprostone orally with food and water to prevent nausea. Swallow the capsule whole. Do not crush, chew, break apart, or open. Take twice a day, in the morning and evening, at least 12 hours apart.


Store Amitiza at room temperature (between 59 F and 86 F) in a tightly closed container, out of the reach of children and pets. Keep it away from direct light and extreme hot or cold temperatures. When traveling by plane, you can transport it in your carry-on or your checked baggage in its original container with labeling. It is recommended to use your carry-on if you might need immediate access.

Off-Label Uses

Healthcare providers may prescribe lubiprostone off-label for medical conditions that it is not approved to treat, but has proven to be beneficial for.

Off-label uses include:

  • Constipation in children: Research has shown that lubiprostone effectively treats constipation in children, even though it is not FDA approved in this population.
  • Irritable bowel syndrome with constipation (IBS-C) in males: These groundbreaking studies, which resulted in Amitiza being approved in females with IBS-C, also had male participants who experienced relief from their symptoms. Unfortunately, there were not enough men represented in the study. Hence, Amitiza is not approved for this population, although it is used off-label.

How Long Does Amitiza Take to Work?

Amitiza absorbs into the blood in about an hour. In most people, it relieves symptoms within the first week after starting. Some people even see an improvement in the first 24 hours after administration.

What Are the Side Effects of Amitiza?

This is not a complete list of side effects, and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at or 1-800-FDA-1088.

Lubiprostone is generally well tolerated. Possible side effects include:

Common Side Effects

More commonly, people who take Amitiza may experience:

  • Nausea
  • Headache
  • Diarrhea

Severe Side Effects

Call your healthcare provider right away if you have serious side effects. Call 911 immediately if your symptoms feel life-threatening or if you think you’re having a medical emergency.

Serious side effects and their symptoms can include:

  • Severe diarrhea
  • Allergic reactions
  • Fainting
  • Low blood pressure

Report Side Effects

Amitiza may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Amitiza Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (soft gelatin capsules):
    • For chronic constipation:
      • Adults—24 micrograms (mcg) two times a day (once in the morning and once in the evening) with food and water.
      • Children—Use and dose must be determined by your doctor.
    • For constipation caused by opioid medicines:
      • Adults—24 micrograms (mcg) two times a day (once in the morning and once in the evening) with food and water.
      • Children—Use and dose must be determined by your doctor.
    • For irritable bowel syndrome (IBS):
      • Adults—8 micrograms (mcg) two times a day (once in the morning and once in the evening) with food and water.
      • Children—Use and dose must be determined by your doctor.


Patients with liver damage may retain more Amitiza than those with normal liver function. The dose of Amitiza should be adjusted in these patients.

Share with your healthcare provider if you are pregnant or if you have plans to become pregnant soon. Amitiza has not yet been thoroughly researched in people who are pregnant. You will need to have a negative pregnancy test before starting lubiprostone. You must also use a birth control method while taking this medication. If you become pregnant while taking lubiprostone, contact your provider right away.

It is currently not known whether Amitiza crosses into breast milk. If your breastfed baby develops diarrhea while you are taking Amitiza, call your healthcare provider.

Missed Dose

If you forget to take a dose of Amitiza, do not panic. You can skip the missed dose and continue with your regular schedule. Do not try to double up to make up for the missed one.

Overdose: What Happens If I Take Too Much Amitiza?

The highest recommended dose of Amitiza is 48 mcg per day. If you take more Amitiza than prescribed, you might experience:

  • Nausea
  • Diarrhea
  • Vomiting
  • Dizziness
  • Headache
  • Stomach pain
  • Hot flashes
  • Shortness of breath

What Happens If I Take Too Much Amitiza?

If you think you or someone else may have overdosed on Amitiza, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Amitiza, call 911 immediately.


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It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

Dizziness, lightheadedness, or fainting may occur, especially when you get up suddenly from a lying or sitting position. These symptoms are more likely to occur when you begin taking this medicine or if you become dehydrated. Getting up slowly may help. Also, lying down for a while may relieve dizziness or lightheadedness.

Lubiprostone may cause difficulty with breathing, nausea, or severe diarrhea. If your symptoms and condition do not improve within a few days, or if they become worse, check with your doctor.

What Are Reasons I Shouldn’t Take Amitiza?

Do not take Amitiza if you have an allergy to lubiprostone or any of its ingredients. If you are allergic, you may break out in a rash, have throat swelling or tightness, or faint. 

You should also not take Amitiza if you have or are suspected to have a blockage in the gut.

Common causes of obstruction include:

What Other Medications Interact With Amitiza?

Lubiprostone’s chemistry makes it a generally well-tolerated medication. It also has a low chance of interacting with other medications. However, there are a few medications that can interact with Amitiza.

Medications that can interact with Amitiza include:


Methadone can reduce how well lubiprostone works. The higher the dose of methadone, the more the chance Amitiza won’t work in combination with it.


Other laxatives similar to Amitiza should not be used with lactulose to avoid extremely loose stools. Lactulose is sometimes used to treat a serious brain illness called encephalopathy. If lubiprostone is used with lactulose in these patients, the loose stools may falsely suggest that the adequate lactulose dosage has been reached.


As the name suggests, antidiarrhea medications (e.g., alosetron, crofelemer) help treat diarrhea. Essentially, they work in opposition to lubiprostone. It would not make sense to take them together. If lubiprostone causes diarrhea as a side effect, simply stopping it should be able to resolve this.


This group of medications blocks a brain hormone called acetylcholine. These drugs can worsen constipation and should not be used with lubiprostone.

Loop Diuretics

Loop diuretics (e.g., bumetanide, torsemide, ethacrynic acid) increase how much water is excreted from the body in the form of urine. They can also lower potassium as this electrolyte follows the water out of the body. Using them with lubiprostone can cause low levels of potassium in the body. Any other medication that can lower potassium should be avoided with lubiprostone.

What Medications Are Similar?

Similar medications to Amitiza include:

  • Cytotec (misoprostol)
  • Linzess (linaclotide)
  • Trulance (plecanatide)

Cytotec (Misoprostol)

Cytotec is a drug in the same class of medications as Amitiza. It is not FDA approved for constipation, but it is sometimes prescribed for off-label use. It is reserved for stubborn cases of constipation. 

Linzess (Linaclotide)

Linzess is not in the same medication class as Amitiza, but it works similarly. It activates receptors in the intestine to increase fluid production and soften stool. It treats long-term constipation and IBS-C. It may be a better choice for those with busy schedules as it only has to be taken once a day and without food. Unlike Amitiza, this capsule can easily be opened up. Those that have trouble swallowing can sprinkle its contents on applesauce to take. 

Trulance (Plecanatide)

Plecanatide is also not in the same medication class as Amitiza, but it works in a similar way. It can manage IBS-C and long-term constipation. Similar to Amitiza, you take it once a day and can split or crush the tablets for easier swallowing. 

This is a list of drugs also prescribed for constipation. It is NOT a list of drugs recommended to take with Amitiza. In fact, you should not take these drugs together. Ask your pharmacist or a healthcare provider if you have questions.

Frequently Asked Questions

  • What is Amitiza used for?

    Amitiza relieves abdominal pain and straining in adults that suffer from long-term constipation. It also makes the stool softer and easier to pass and treats constipation caused by certain pain medications and irritable bowel syndrome with constipation in women.

  • How does Amitiza work?

    Amitiza works by increasing the amount of fluid in the bowels. It achieves this by activating receptors in the intestine to produce more chloride.

  • How long does it take for Amitiza to work?

    Symptoms should start resolving within the first week of starting Amitiza.

How Can I Stay Healthy While Taking Amitiza?

Everyone has experienced constipation at one time or another in their life. In most cases, constipation is a temporary condition treated with diet changes, exercise, or taking over-the-counter (OTC) products.

Eating more fiber can help encourage bowel movements. Foods containing fiber include:

  • Prunes
  • Figs
  • Licorice
  • Cereal
  • Whole-grain bread
  • Fresh fruits
  • Legumes (beans and lentils)

Some people use OTC fiber supplements and laxatives to ease symptoms as well. Talk to your healthcare provider about what the best option for you might be. Treating chronic constipation is often more complicated. This is where Amitiza comes in.

Remember to take Amitiza twice a day as directed by your healthcare provider. If you keep forgetting to take it, consider setting alarms or reminders. Ask your doctor or pharmacist any questions you might have about the medication.

Medical Disclaimer

Verywell Health's drug information is meant for education purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bharucha AE, Dorn SD, Lembo A, Pressman A. American gastroenterological Association medical position statement on constipation. Gastroenterology. 144(1), 211–217. 2013.

  2. Food and Drug Administration. Amitiza label. Updated November 2020.

  3. Hyman PE, Lorenzo CD, Prestridge LL, et al. Lubiprostone for the treatment of functional constipation in children. J Pediatr Gastroenterol Nutr. 2014 Mar;58(3):283-921). Doi: 10.1097/MPG.0000000000000176

  4. Lopez-Kostner F, Hool GR, Lavery IC. Management and causes of acute large-bowel obstruction. Surg Clin North Am. 1997;77(6):1265-1290. doi:10.1016/s0039-6109(05)70617-4