Vumerity (diroximel fumarate) can cause side effects that range from mild to serious. Common side effects include flushing and diarrhea. If side effects become bothersome, talk with your doctor about tips for managing them or other treatment options.

Vumerity is used in adults to treat the following relapsing forms of multiple sclerosis (MS):

Vumerity is also prescribed to treat clinically isolated syndrome (CIS) in adults. This is a condition that may develop into MS.

The active ingredient in Vumerity is diroximel fumarate. Vumerity comes as a delayed-release capsule. (This type of capsule resists stomach acid, so it can release the drug in your intestines instead.)

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

Some people may experience mild to serious side effects during Vumerity treatment. Examples of the drug’s commonly reported side effects include:

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

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

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

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

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

Serious side effects have been reported with Vumerity. These include:

If you develop serious side effects while taking Vumerity, 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.

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

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 Vumerity, visit MedWatch.

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

No, cancer wasn’t a side effect reported in Vumerity’s studies. But Vumerity can weaken your immune system, which can make it more difficult for your body to fight cancer cells.

Certain other drugs used to treat MS may increase the risk of some kinds of cancer. These drugs include:

Talk with your doctor or pharmacist if you have questions about possible side effects of drugs prescribed to treat MS.

How do side effects of Vumerity compare with those of Tecfidera or Ocrevus?

Vumerity, Tecfidera, and Ocrevus are prescribed to treat certain forms of MS.

Vumerity’s and Tecfidera’s side effects are expected to be the same. Vumerity contains the active ingredient diroximel fumarate, and Tecfidera contains the active ingredient dimethyl fumarate. Your body turns both of these ingredients into monomethyl fumarate (MMF). So whether you take a dose of Vumerity or a dose of Tecfidera, your body ultimately changes it into MMF, which is what works to treat MS.

Ocrevus side effects are mostly similar to those of Vumerity and Tecfidera, but there are some different ones as well. For example, mild respiratory infections (such as the common cold) occurred frequently in studies of Ocrevus, but they weren’t reported with Vumerity or Tecfidera. And Ocrevus may raise the risk of certain cancers, while Vumerity isn’t thought to. (See the “Does Vumerity cause cancer?” FAQ.)

Talk with your doctor or pharmacist to learn more about how side effects of different MS drugs compare to one another.

Does Vumerity cause weight gain or weight loss?

No, it’s not thought to. Weight changes weren’t a side effect reported in Vumerity’s studies.

Corticosteroids, such as prednisone, are commonly prescribed to treat MS, and these drugs are known to cause weight gain.

According to the National Multiple Sclerosis Society, it’s not unusual for people with MS to experience weight gain due to symptoms of the condition. For example, some symptoms of MS, such as tiredness and depression, can make it harder to engage in physical activity. So effectively treating your MS could potentially lead to weight loss.

Talk with your doctor if you have concerns about your weight or would like to know whether any drugs you take could cause weight changes.

Does Vumerity cause long-term side effects?

It’s possible. Long-term side effects include those that may start at any time you’re taking a drug, even if you’ve taken it for a long time. It also includes side effects that may not go away, even after you stop taking the drug.

Examples of long-term side effects reported in Vumerity’s studies include:

  • liver damage*
  • lymphocytopenia (a low level of lymphocytes, a type of white blood cell)

Talk with your doctor to learn more about possible side effects of Vumerity and how long they may last.

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

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

Flushing

Flushing was the most common side effect reported in studies of Vumerity. Flushing may cause temporary symptoms such as:

  • warmth
  • skin redness or discoloration
  • an itching or burning sensation (anywhere in the body)

According to the drug’s studies, flushing is most likely to occur when you first start taking Vumerity. It typically goes away on its own as you continue treatment.

What might help

If you have flushing during Vumerity treatment, consider the following options to help relieve your symptoms:

  • take your Vumerity doses with food
  • if your doctor says it’s safe for you, take one dose of regular aspirin (up to 325 mg) about 30 minutes before your Vumerity doses

If you have flushing that’s bothersome or doesn’t go away, tell your doctor. They may recommend stopping treatment with Vumerity and exploring other MS treatments instead.

Liver damage

In studies of Vumerity, liver damage was rare. Symptoms include:

If you have an existing liver condition, taking Vumerity could worsen it. You may also have an increased risk of new liver problems with this medication.

What might help

Your doctor will likely order blood tests to check your liver enzyme levels before prescribing Vumerity for you. If your enzyme levels are high, your doctor may prescribe a different MS treatment for you.

During treatment, your doctor will continue to order these tests to check your liver health. Let them know right away if you think you’re having symptoms of liver damage.

Allergic reaction

Like most drugs, Vumerity can cause an allergic reaction in some people, but these reactions were rare in studies. 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 oral antihistamine, 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 Vumerity, they’ll decide whether you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty 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 Vumerity, they may have you switch to a different treatment.

Keeping track of side effects

During Vumerity 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 a new drug or 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

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

Vumerity can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether this drug is a good treatment option for you.

Talk with your doctor about your health history before starting Vumerity. Be sure to tell them if any of the following factors apply to you:

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.