If you have ulcerative colitis (UC), your doctor might suggest Apriso (mesalamine) as a treatment option for you. It’s a prescription medication that’s used to maintain remission of UC in adults. Remission refers to a period when you don’t have any UC symptoms.

Apriso comes as an extended-release (ER) capsule that you swallow. ER means that the capsule releases the drug slowly over time.

The active drug in Apriso is mesalamine, which is also available in generic form. Mesalamine belongs to a group of drugs called aminosalicylates.

For more information about Apriso, see this in-depth article on the drug.

Like other drugs, Apriso can cause mild or serious side effects. Keep reading to learn more.

Some people may experience mild or serious side effects during their Apriso treatment. Examples of Apriso’s commonly reported side effects include:

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

Examples of mild side effects that have been reported with Apriso include:

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

In most cases, these side effects are temporary. And some may be easily managed. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop taking Apriso unless your doctor recommends it.

Apriso may cause mild side effects other than the ones listed above. See the Apriso prescribing information for details.

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 Apriso, visit MedWatch.

Although serious side effects can occur, these were rare in studies of the drug.

Serious side effects that have been reported with Apriso include:

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

* To learn more about this side effect, see the “Side effects explained” section below.
† An allergic reaction is possible after you take Apriso. But it’s not clear whether this side effect occurred in studies.

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

Is weight gain a side effect of Apriso?

No, weight gain wasn’t a side effect reported by people taking Apriso in studies.

Keep in mind that Apriso works to keep ulcerative colitis (UC) symptoms in remission. This refers to a time when you’re not having any symptoms. So you may find that you’re able to eat more than you did when your UC symptoms were causing problems. This could lead to weight gain.

If you’re concerned about weight gain or have questions about your weight, talk with your doctor. They can recommend ways to reach or maintain a weight that is healthy for you.

Does Apriso cause any long-term side effects?

It’s possible for some side effects of Apriso to be long term. These are side effects that either continue for a long time or start after you’ve taken Apriso for a long time.

Apriso may cause the following long-term side effects:

For details about kidney problems and Apriso, see “Side effects explained” below. And for more information about liver failure, see “Warnings for Apriso” below.

If you have questions about long-term side effects of Apriso, talk with your doctor or pharmacist.

Will I experience side effects if I stop taking Apriso?

No, stopping Apriso treatment isn’t expected to cause side effects. Withdrawal symptoms weren’t reported in the drug’s studies. These are side effects that can happen when you stop taking a drug that your body has become dependent on.

Stopping Apriso can cause your UC symptoms to become active again. But this isn’t the same as having withdrawal symptoms.

If you have questions about stopping Apriso treatment, talk with your doctor or pharmacist. You should not stop taking Apriso or any other prescription medications without first talking with your doctor.

Can Apriso cause appetite loss?

No, Apriso isn’t known to cause appetite loss. This wasn’t reported in studies.

Appetite loss is a known side effect of Azulfidine (sulfasalazine), which is another drug used to treat UC. Apriso and sulfasalazine belong to the same group of drugs, called aminosalicylates.

It’s also important to note that nausea and upper belly pain are possible side effects of Apriso. For some people, these side effects could result in a decreased appetite.

If you’re concerned about appetite loss and your UC treatment, talk with your doctor.

Learn more about some of the side effects that Apriso may cause.

Hair loss

Hair loss is a rare side effect of Apriso.

In studies, researchers didn’t note how long hair loss lasted, what parts of the body were affected, or whether the hair loss stopped after people stopped taking the drug.

It’s important to note that hair loss has been reported at higher than usual rates in people with inflammatory bowel disease, such as ulcerative colitis (UC).

What might help

Talk with your doctor if you experience hair loss while taking Apriso. They may recommend a treatment for this side effect. Or they may suggest that you stop taking Apriso and try a different medication for your UC.


It’s possible that you’ll have a headache as a side effect of Apriso. This was the most common side effect reported in studies.

A headache can also be a symptom of a rare side effect of Apriso called mesalamine-induced acute intolerance syndrome. This condition is a reaction to Apriso’s active drug, and it’s discussed in detail just below.

What might help

A headache caused by Apriso may go away on its own after a few hours.

If you have an occasional mild headache while taking Apriso, you may be able to use an over-the-counter treatment. Examples include ibuprofen (Advil, Motrin) and acetaminophen (Tylenol). But be sure to talk with your doctor or pharmacist first. They can make sure that these medications are safe for you.

You can also try non-medication treatments for a headache. Examples include a hot or cold compress or doing a relaxing activity, such as yoga.

If you have headaches that occur often or don’t go away with the above treatments, talk with your doctor. In this case, they may suggest trying a treatment other than Apriso for your UC symptoms.

Mesalamine-induced acute intolerance syndrome

Mesalamine-induced acute intolerance syndrome is a rare side effect of Apriso. This condition develops quickly, and its symptoms can be similar to severe UC symptoms.

The symptoms can include:

What might help

If you develop symptoms of mesalamine-induced acute intolerance syndrome, contact your doctor. They’ll likely want to examine you to determine the cause.

If your doctor determines that you likely have mesalamine-induced acute intolerance syndrome, they’ll recommend that you stop taking Apriso.

Kidney damage

Rarely, kidney damage can be a side effect of Apriso. This can include kidney failure in extreme cases.

Symptoms of kidney damage can include:

  • confusion
  • fatigue (low energy)
  • nausea or vomiting
  • swelling in your feet, ankles, and legs
  • urinating less than usual

What might help

Your doctor will likely check your kidney function before prescribing Apriso. And they may continue checking your kidney function while you’re taking it. This is to make sure that your kidneys remain healthy enough for you to take the drug.

Contact your doctor right away if you think you’re having symptoms of kidney damage while taking Apriso. If they confirm that you’re having kidney problems due to Apriso, they’ll likely have you stop taking the drug.

Allergic reaction

Like most drugs, Apriso can cause an allergic reaction in some people. It’s not clear whether this side effect occurred in studies.

Symptoms can be mild or serious and can include:

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

In some cases, it’s possible for a serious allergic reaction to Apriso to cause inflammation (swelling and damage) in your:

  • heart
  • kidneys
  • liver
  • lungs

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may recommend an over-the-counter oral antihistamine, such as Benadryl (diphenhydramine), to manage your symptoms. Or they may suggest a product that you apply to your skin, such as hydrocortisone cream.

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 that you had a serious allergic reaction to Apriso, they may have you switch to a different treatment.

Keeping track of side effects

During your Apriso treatment, consider keeping notes about any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things like:

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

Keeping notes and sharing them with your doctor will help them learn more about how Apriso affects you. And your doctor can use this information to adjust your treatment plan if needed.

Apriso may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Apriso. The list below includes factors to consider.

Kidney problems. Treatment with Apriso can cause kidney problems, including kidney failure, in rare cases. If you already have kidney problems, such as chronic kidney disease, you may have a higher risk of this side effect with Apriso. Your doctor can help determine whether taking Apriso is safe for you.

Liver problems. There have been rare reports of liver failure in people with existing liver problems who took Apriso. Be sure to tell your doctor about any liver problems you may have, such as hepatitis. Your doctor can help determine whether Apriso is safe for you.

Phenylketonuria (PKU). Apriso contains phenylalanine, and taking the drug may cause a buildup of this protein in your body. This buildup can cause serious problems, such as seizures, if you have PKU. Your doctor will consider all of your sources of phenylalanine before determining whether Apriso is safe. They may monitor your PKU closely if they prescribe Apriso for you.

Skin conditions, such as eczema. Apriso can cause increased sensitivity to sunlight. If you have a skin condition, such as eczema, you may be more likely to have this side effect, and it’s more likely to be severe. Your doctor can help determine whether Apriso is safe for you.

Allergic reaction. If you’ve had an allergic reaction to Apriso or any of its ingredients, your doctor will likely not prescribe Apriso. Ask them what other medications are better options for you.

Alcohol use and Apriso

There’s no known interaction between drinking alcohol and taking Apriso.

But Apriso and alcohol can cause similar side effects, including nausea and headache. It’s possible that drinking alcohol could increase your risk of these side effects. Alcohol can also make UC symptoms worse in some cases, so it’s important to talk with your doctor about your alcohol use.

If you drink alcohol, talk with your doctor about how much is safe for you to drink while you’re taking Apriso.

Pregnancy and breastfeeding while taking Apriso

It isn’t known whether it’s safe to take Apriso while pregnant or breastfeeding. There are reports of diarrhea in breastfed children exposed to mesalamine, the active drug in Apriso.

If you’re pregnant, breastfeeding, or planning either, talk with your doctor before starting treatment with Apriso.

Like most drugs, Apriso can cause side effects. If you do have side effects, they’re likely to be mild and go away on their own. Serious side effects of the drug are rare.

If you have questions about Apriso’s side effects, talk with your doctor or pharmacist. Ask questions to get the answers you need to feel confident about your treatment. Here are a few to get you started:

  • Can other medications I take increase my risk of side effects from Apriso?
  • How can I tell the difference between worsening ulcerative colitis (UC) symptoms and mesalamine-induced intolerance syndrome caused by Apriso?
  • Does my age increase my risk of side effects from Apriso?
  • Will taking Apriso with food help prevent or treat side effects?

To learn more about managing inflammatory bowel disease (IBD), such as UC, sign up for Healthline’s IBD newsletter.


Will I have to stay out of the sun if I take Apriso?



While you take Apriso, you should avoid prolonged sun exposure. A possible side effect of Apriso is increased sensitivity to sunlight. This can cause symptoms such as an itchy rash or skin discoloration.

If you’re exposed to the sun, be sure to wear protective clothing, such as long sleeves and a hat. You should also use sunscreen any time you’re outside.

Dena Westphalen, PharmDAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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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.