Amitiza (lubiprostone) is a prescription drug that’s used to treat certain kinds of constipation in adults. Amitiza can cause side effects that range from mild to serious. Examples include nausea and diarrhea.

Amitiza is used in adults to treat:

The active ingredient in Amitiza is lubiprostone. (An active ingredient is what makes a drug work.) The drug comes as a capsule you swallow.

Keep reading to learn about the common, mild, and serious side effects Amitiza can cause. For a general overview of the drug, including details about its uses, see this article.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Below are just a few of the more common side effects reported by people taking Amitiza in studies.

Most of the common side effects of this drug are the same, regardless of the condition it’s being used to treat. But a couple of side effects are more common when the drug is used to treat certain conditions.

For instance, headache is a side effect that’s common only when Amitiza is taken for chronic idiopathic constipation. And passing gas is a common side effect when the drug is taken for opioid-induced constipation.

Side effects that are common for all conditions include:

* To learn more about this side effect, see the “Side effects explained” section below.

Mild side effects have been reported with Amitiza. These include:

* To learn more about this side effect, see the “Side effects explained” section below.

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And do not stop taking Amitiza unless your doctor recommends it.

Amitiza may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Serious side effects have been reported with Amitiza. Some serious side effects are more common in people who are taking blood pressure medications as well as Amitiza. People with certain digestive problems can also have serious side effects with Amitiza. Some side effects resolve on their own, while others may continue throughout treatment with this drug.

Serious side effects of Amitiza include:

* To learn more about this side effect, see the “Side effects explained” section below.

If you develop serious side effects while taking Amitiza, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Amitiza, visit MedWatch.

Get answers to some frequently asked questions about Amitiza’s side effects.

How do side effects of Amitiza compare with those of Linzess?

The side effects of Linzess and Amitiza are similar. Common side effects of both drugs include diarrhea, passing gas, and bloating. Diarrhea with either Amitiza or Linzess is usually mild but can be severe.

A major difference between the side effects of Linzess and Amitiza are those seen in children. For example, Linzess can cause severe dehydration in children. Talk with your doctor if you have questions about how side effects of Amitiza compare with those of other treatment options for your condition.

What are the signs or symptoms that Amitiza is not working?

If Amitiza isn’t working, your constipation may not improve. You may continue to have trouble passing stools or with infrequent bowel movements. You may also feel like you haven’t emptied your bowels completely.

Can Amitiza cause weight gain or weight loss?

Amitiza can cause weight gain but this isn’t a common side effect. Some people may lose their appetite with this drug, which can cause weight loss. But this isn’t a common side effect either. If you’re concerned about how Amitiza may affect your weight, talk with your doctor. They can suggest ways to help you reach and maintain a moderate weight.

Do side effects of Amitiza go away?

Some side effects of Amitiza may go away. For example, nausea can go away if you take this drug with food. Some serious side effects may also go away. For example, some people may experience trouble breathing within an hour of taking their first dose of Amitiza. But this usually resolves after a few hours. Still, it’s possible that issues such as trouble breathing and fainting may reoccur following future doses of this drug.

Learn more about some of the side effects Amitiza may cause.

Bloating

Bloating is a common side effect reported in Amitiza studies. This is an uncomfortable but generally harmless side effect of this drug.

What might help

A few tips to help control bloating with Amitiza include:

  • avoiding foods that aggravate this condition, such as beans and dairy products
  • exercising regularly
  • improving your posture

Talk with your doctor or pharmacist if you continue to have bothersome bloating with this medication.

Diarrhea

Diarrhea is a common and usually mild side effect of Amitiza. But sometimes it can be severe and may require hospitalization.

Some people also had diarrhea before experiencing low blood pressure and fainting. And having diarrhea can increase your risk of these side effects.

What might help

Before taking over-the-counter medications such as Imodium (loperamide), talk with your doctor. (This drug isn’t safe for certain kinds of diarrhea, such as infectious diarrhea.) Your doctor will tell you if Imodium is safe for you.

If you have diarrhea, you can help prevent dehydration by sipping broths and sports drinks. These help replace the fluid and electrolytes you’ve lost in your stool.

If you have severe diarrhea, call your doctor right away. You may need to receive fluids through an injection into your vein. Your doctor may have you stop taking Amitiza, either temporarily while you have diarrhea or permanently. But do not stop taking this drug without talking with them first. Stopping Amitiza can make your condition worse.

Low blood pressure and fainting

Some people in Amitiza’s studies experienced low blood pressure and fainting. In some situations, they were hospitalized because of these side effects. Some of these people were taking blood pressure medications as well as Amitiza, which can increase the risk of these side effects.

It was usually people taking a higher dose of Amitiza twice per day who experienced low blood pressure and fainting. These side effects usually occurred within an hour of the person taking the drug.

What might help

In Amitiza’s studies, these side effects usually went away after the person stopped taking the drug or before taking their next dose. But some people had repeated episodes of fainting and low blood pressure following doses of Amitiza.

Tell your doctor if you’re taking any blood pressure medications. If you faint or feel like you’re going to after taking Amitiza, tell your doctor right away. And be sure to ask them how often you should check your blood pressure while taking this drug.

Allergic reaction

Like most drugs, Amitiza can cause an allergic reaction in some people. Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an antihistamine you swallow, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Amitiza, they’ll decide if you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Amitiza, they may have you switch to a different treatment.

Keeping track of side effects

During your Amitiza treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Taking notes and sharing them with your doctor will help them learn more about how Amitiza affects you. They can then use this information to adjust your treatment plan if needed.

Amitiza may not be right for you if you have certain medical conditions. (This is known as a drug-condition interaction.) Other factors may also affect whether Amitiza is a good treatment option for you. Talk with your doctor about your health history before starting this drug. Factors to consider include those described below.

Severe diarrhea. If you have severe diarrhea, Amitiza may not be right for you. Diarrhea is a common side effect of this drug and taking it if you already have diarrhea can make the condition worse. Due to this risk, doctors usually will not prescribe Amitiza if you have diarrhea.

Allergic reaction. If you’ve had an allergic reaction to Amitiza or any of its ingredients, your doctor will likely not prescribe it for you. Ask them about other medications that might be better options.

Bowel obstruction (intestinal blockage). If you have symptoms of a bowel obstruction, your doctor will examine you thoroughly before prescribing Amitiza for you. A bowel obstruction can prevent digested food from moving through your digestive tract. Symptoms include abdominal pain, nausea, and vomiting. If your physical exam shows signs of intestinal blockage, your doctor will likely not prescribe Amitiza for you.

Alcohol and Amitiza

Some medications interact with alcohol, but Amitiza isn’t one of them. If you drink, talk with your doctor or pharmacist before starting Amitiza to find out how much, if any, is safe.

Pregnancy and breastfeeding while taking Amitiza

It’s not known if Amitiza is safe to take during pregnancy. If you’re pregnant or considering pregnancy, talk with your doctor before starting this medication.

It’s also not known if Amitiza is found in breastmilk or if the drug affects breastmilk production. There also aren’t many studies on the effects of Amitiza on children who are breastfed.

If you’re breastfeeding or considering it, talk with your doctor before starting Amitiza. They’ll help you decide if the benefits of breastfeeding outweigh the possible risks to your child. Or they’ll suggest a different treatment for your condition.

Side effects are common with Amitiza but they’re usually mild. Serious side effects sometimes go away while others continue after the first dose. If you have questions about side effects this drug can cause, talk with your doctor. Examples of questions to help get you started include:

  • Can Amitiza cause sexual side effects?
  • How do the side effects of the 8-milligram (mg) dose compare with the 24-mg dose?
  • Can Amitiza cause constipation?

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.