Casodex (bicalutamide) is a prescription drug used to treat prostate cancer. Casodex can cause side effects that range from mild to serious. Examples include infection, shortness of breath, and constipation.

Specifically, Casodex, combined with luteinizing hormone-releasing hormone (LHRH), is used in adults to treat stage D2 prostate cancer that’s metastatic (has spread to other parts of the body).

The active ingredient in Casodex is bicalutamide. The drug comes as a 50-milligram (mg) oral tablet.

Keep reading to learn about the common, mild, and serious side effects the Casodex 50-mg dose can cause. For a general overview of the drug, including details about its uses, see this article.

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

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

Casodex 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 Casodex. These include:

Some of these, such as breast enlargement and liver injury, may become long-term side effects.

If you develop serious side effects while taking Casodex, 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 below.
† In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.
‡ To learn more about this side effect, see the “Pregnancy and breastfeeding with Casodex” section below.

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 Casodex, visit MedWatch.

Allergic reaction

For some people, Casodex can cause an allergic reaction. This side effect wasn’t reported in the drug’s studies but was reported after the drug came on the market.

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

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 keep taking Casodex.

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

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

What foods should I avoid when taking Casodex?

Casodex can generally be taken with or without food. Studies didn’t find any interactions between Casodex and certain foods. But because Casodex can increase effects of estrogen in your body, you may benefit from avoiding foods containing estrogen.

If you have questions about foods to avoid during Casodex treatment, check with your doctor, dietician, or pharmacist.

Will I have side effects after stopping Casodex?

Studies didn’t report any side effects caused by stopping Casodex. But, since it takes approximately 30 days to clear the drug from your body, you may still have side effects during this time. Side effects could possibly even extend beyond those 30 days, depending on how long you’ve taken Casodex.

These lingering side effects include breast pain and swelling, hot flashes, elevated liver enzyme levels, lack of sex drive, and impotence.

Each person may have different side effects after stopping Casodex. Check with your doctor or pharmacist if you have questions about what to expect.

Does Casodex cause problems with dental treatments?

For people with advanced prostate cancer that has spread to the bones, the combination of Casodex with LHRH may contribute to weakened bones.

To help strengthen bones, your doctor may prescribe a type of medication called a bisphosphonate. But a common side effect of bisphosphonates is a condition called osteonecrosis of the jaw.

Osteonecrosis can develop from having invasive dental work while taking Casodex with LHRH and bisphosphonates. Your doctor may advise you to have a thorough dental checkup and correct any problems before starting prostate cancer treatment.

You may lower your risk of osteonecrosis by brushing, flossing, and having regular dental appointments.

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

Increased blood sugar levels

Increased blood sugar levels were a common side effect reported in studies of Casodex.

Increased blood sugar levels may cause symptoms such as:

Factors that can raise the risk of increased blood sugar levels while taking this drug include:

  • smoking
  • being age 65 years or older
  • family history of high blood sugar
  • obesity or being overweight
  • physical inactivity
  • ethnic background, such as Native American, Black American, or Latino/Hispanic American

What might help

If you have symptoms of increased blood sugar during Casodex treatment, talk with your doctor right away. They’ll likely recommend an office visit to discuss your symptoms and possible treatment.

Breast enlargement

Breast enlargement was a common side effect reported in studies of Casodex. And it’s a common side effect with long-term use, according to a 2017 study published in the New England Journal of Medicine.

Breast enlargement may cause symptoms such as:

Factors increasing the likelihood of breast enlargement while taking Casodex include:

  • being age 65 years or older
  • taking other medications that enlarge breast tissue, such as corticosteroids
  • alcohol use
  • high percentage of body fat
  • taking a 150-mg dose of Casodex*

* Casodex’s prescribing information states that this is not an approved dose of the drug, but some doctors may prescribe it in certain situations.

What might help

If you have breast enlargement during Casodex treatment, consider the following tips to reduce breast size:

  • use a chest binder
  • reduce intake of foods that contain natural estrogens, such as soy products and flaxseeds
  • increase aerobic exercise to reduce body fat
  • eat a balanced diet
  • reduce alcohol use

If you develop a breast lump or nipple discharge, talk with your doctor right away. They’ll likely recommend a medical evaluation for breast cancer screening.

Liver injury

Liver injury was a rare side effect reported in studies of Casodex.

Liver injury may cause symptoms such as:

Some people progressed to hepatitis (liver inflammation), liver failure, and death.

Factors that can increase the risk of liver injury when taking this drug include:

What might help

Liver injury usually occurs within the first 3 to 4 months of Casodex treatment. Your doctor will order liver function tests before you start Casodex, regularly during the first 4 months of treatment, and then as needed.

If you have symptoms of liver injury during Casodex treatment, talk with your doctor right away. They’ll likely recommend an urgent medical evaluation to check your liver enzyme blood levels and start appropriate treatment.

Keeping track of side effects

During your Casodex 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

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

Below is important information you should consider before taking Casodex.

Warnings

Casodex 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 Casodex. Be sure to tell them if any of the following factors apply to you:

  • diabetes
  • moderate to severe liver disease
  • planning to have children
  • having a female partner who can become pregnant
  • taking a blood thinner
  • taking other prescription medications, over-the-counter (OTC) drugs, herbs, vitamins, or dietary supplements
  • being lactose intolerant (lactose is an inactive ingredient of Casodex tablets)
  • previous allergic reaction to Casodex
  • pregnancy
  • breastfeeding

Alcohol and Casodex

There are no known interactions between alcohol and Casodex. But liver problems or damage may occur while taking Casodex and also from drinking excessive amounts of alcohol. Alcohol may also increase Casodex’s side effects of sleepiness, hot flashes, dizziness, nausea, and vomiting.

If you have questions about consuming alcohol during Casodex treatment, talk with your doctor or pharmacist.

Pregnancy and breastfeeding with Casodex

Females, especially if they’re pregnant or breastfeeding, should not take Casodex. Note that Casodex is not approved for use in females, as this drug is only used to treat prostate cancer.

Pregnancy

Casodex can deform sperm cells, leading to problems with fetal development (commonly known as birth defects). If your partner is able to become pregnant, your doctor may recommend that you both use a form of birth control during your Casodex treatment. And you both may need to continue using it for 130 days after your treatment ends.

Casodex can also lead to problems with sperm production and may make it harder to conceive. If you’re planning on trying to conceive, talk with your doctor about using Casodex.

Casodex is not safe to take during pregnancy because it can cause harm to a fetus.

Breastfeeding

Casodex is not safe to take while breastfeeding. The drug can pass into breast milk and may harm a child who’s breastfed.

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.