Xtandi (enzalutamide) is a brand-name drug that’s prescribed to treat prostate cancer in certain adults. As with other drugs, Xtandi can cause side effects, such as fatigue, headache, and hot flashes.

Xtandi can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Xtandi in clinical trials:

  • fatigue
  • diarrhea
  • muscle pain or weakness
  • headache
  • hot flashes (see “Side effect specifics” below)

Mild side effects can occur with Xtandi use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Xtandi’s prescribing information.

Mild side effects that have been reported with Xtandi include:

  • fatigue
  • diarrhea
  • muscle pain or weakness
  • headache
  • decreased appetite
  • dizziness
  • joint or back pain
  • high blood pressure
  • weight loss
  • hot flashes (see “Side effect specifics” below)

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Xtandi and want to tell the FDA about it, visit MedWatch.

Xtandi may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Xtandi’s prescribing information.

If you develop serious side effects while taking Xtandi, 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.

Serious side effects that have been reported and their symptoms include:

  • seizures, which may include symptoms such as:
    • confusion
    • loss of consciousness
    • rapid eye movements
    • repeated jerking movements
  • posterior reversible encephalopathy syndrome (PRES), a type of swelling in the brain, which may include symptoms such as:
    • tiredness
    • confusion
    • seizures
    • headache
    • vision changes
  • falls, which can increase your risk of bone fractures
  • ischemic heart disease (see “Side effect specifics” below)
ALLERGIC REACTION

For some people, Xtandi can cause an allergic reaction.

In general, symptoms of allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Xtandi, your doctor may recommend taking a different medication instead.

Xtandi may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How long do the side effects of Xtandi last?

Side effects of Xtandi will generally go away soon after you stop taking it. However, if you experience hot flashes with Xtandi treatment, they may continue for a few months or longer after treatment ends. For details about hot flashes with Xtandi, see the “Side effects specifics” section below.

Talk with your doctor or pharmacist for more information on how long Xtandi side effects may last.

Does Xtandi 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. They also include side effects that may not go away even after you stop taking the drug.

An example of a long-term side effect reported in Xtandi’s clinical trials is PRES. With treatment, the symptoms generally go away within days to weeks. But in rare cases, PRES can lead to blindness and even death.

Also, ischemic heart disease can develop during Xtandi treatment. This may cause effects that will need treatment in the long term. See “Side effect specifics” below for more information on ischemic heart disease.

Talk with your doctor if you have questions or concerns about the long-term side effects of Xtandi.

Will stopping Xtandi treatment cause side effects?

It’s unlikely. Withdrawal side effects were not reported in Xtandi’s clinical trials. (“Withdrawal” refers to side effects that occur when you stop taking a drug.) If you have side effects with Xtandi treatment, they should go away after you stop treatment.

Rarely, stopping Xtandi or other hormone treatments can cause antiandrogen withdrawal syndrome (AAWS).

In AAWS, your prostate-specific antigen (PSA) levels decrease, and your cancer symptoms may ease. (PSA is a protein that’s measured to determine the risk of having prostate cancer.) This isn’t common, and researchers don’t know why it happens in certain people. So it’s important that you don’t stop taking Xtandi unless your doctor advises you to do so.

If you have any questions or concerns about stopping Xtandi treatment, talk with your doctor or pharmacist.

Learn more about some of the side effects that Xtandi may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Xtandi.

Hot flashes

Hot flashes were a commonly reported side effect of Xtandi in the drug’s clinical trials. A hot flash is a sudden feeling of intense warmth or heat. It can often affect your face, chest, arms, and back. Other symptoms of a hot flash may include:

  • sweating
  • dizziness
  • redness or other color changes in your skin

A hot flash tends to pass within minutes and may end in a cold sweat.

What you can do

Lifestyle habits such as eating a low fat diet, exercising regularly, and getting good quality sleep may help relieve mild symptoms of hot flashes. Avoiding triggers such as spicy foods, hot drinks, and alcohol might also help. Additionally, you may find it helpful to wear loose-fitting clothing, dress in layers, or use fans to stay cool.

Talk with your doctor if your symptoms are severe or affect your daily life. They may recommend treatment to help manage your hot flashes.

Ischemic heart disease

Some people taking Xtandi have developed ischemic heart disease. This wasn’t common in the drug’s clinical trials.

Ischemic heart disease occurs when a blockage forms in the arteries that deliver blood to your heart. If these arteries narrow, your heart may not get enough blood and oxygen, especially during physical activity. In rare cases, this condition may lead to heart attack or death.

Symptoms of ischemic heart disease may include:

  • shortness of breath
  • chest pain or pressure
  • lightheadedness or dizziness
  • tiredness
  • heart palpitations (the feeling of a racing, pounding, or fluttering heartbeat)

Smoking and certain health conditions, such as high blood pressure, high cholesterol, and diabetes, may raise your risk of ischemic heart disease.

What you can do

If you have any of the above risk factors, your doctor will want to make sure these conditions are well managed. This may involve taking medications or making lifestyle changes, such as eating a healthy diet, exercising regularly, and stopping smoking. Taking these steps can help reduce your risk of developing ischemic heart disease.

If you experience any symptoms of ischemic heart disease, talk with 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.

Below is important information you should consider before taking Xtandi.

Other precautions

Before taking Xtandi, discuss your health history with your doctor. Xtandi may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Disclaimer: Medical News Today 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.