Reblozyl (luspatercept-aamt) is a prescription drug used to treat anemia in adults with certain blood disorders. Reblozyl can cause side effects that range from mild to serious. These include dizziness and tiredness.

Reblozyl is used in adults to treat anemia caused by certain blood disorders, such as:

The active ingredient in Reblozyl is luspatercept-aamt. (The “-aamt” appears at the end of the drug’s name to show it’s distinct from similar drugs that may be created in the future.) Reblozyl is a biologic medication made from living cells. The drug comes as an injection that’s given under the skin by a healthcare professional.

Keep reading to learn about common, mild, and serious side effects that Reblozyl can cause.

For a detailed overview of this drug, including its mechanism of action (how it works), dosages, and more, check out this in-depth Reblozyl article.

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

Mild side effects have been reported with Reblozyl. 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 Reblozyl treatment unless your doctor recommends it.

Reblozyl 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 Reblozyl. These include:

If you develop serious side effects while taking Reblozyl, 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.
† EMH masses happen when blood cells are made outside the bone marrow. This can lead to masses occurring on certain organs such as your liver or spleen. You have a higher risk of EMH masses if you’ve had them in the past or have had your spleen removed. Your risk is also higher if you have beta thalassemia, an enlarged liver or spleen, or low hemoglobin levels.

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 Reblozyl, visit MedWatch.

ALLERGIC REACTION

For some people, Reblozyl can cause an allergic reaction.

In general, symptoms of allergic reaction can be mild or serious.

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 and can determine whether you should continue Reblozyl treatment.

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 Reblozyl, they may have you switch to a different treatment.

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

High blood pressure

High blood pressure was a serious side effect reported in studies of Reblozyl. This condition typically doesn’t cause symptoms.

However, symptoms of very high blood pressure may include:

What might help

If you have a history of high blood pressure, tell your doctor. They’ll determine whether Reblozyl is safe for you. They may have you monitor your blood pressure regularly if they prescribe this medication for you.

If you experience symptoms of very high blood pressure, call 911 or go to the nearest emergency medical center immediately. Severe high blood pressure can be life threatening if not treated promptly.

Blood clots

Treatment with Reblozyl may increase the risk of blood clots in your lungs, brain, or veins. This is a rare but serious side effect of the medication reported in studies.

Symptoms may include:

  • shortness of breath
  • chest pain
  • chest heaviness
  • pain or swelling in your leg or abdomen
  • face weakness
  • rapid heart rate
  • nausea
  • difficulty speaking
  • arm or leg weakness

Your risk of blood clots is higher if any of the following apply:

What might help

Talk with your doctor about your health history and about all medications you take. They’ll determine whether Reblozyl is safe for you. In certain cases, they may prescribe a blood thinner to help lower your risk of blood clots.

If you have symptoms of a blood clot that feel life threatening, call 911 or go to your nearest emergency medical center.

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

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

  • kidney problems
  • high blood pressure
  • previous allergic reaction to Reblozyl
  • history of blood clots
  • history of EMH masses
  • enlarged spleen or liver or had your spleen removed
  • pregnancy
  • breastfeeding

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.