Enzalutamide (Xtandi®)

Most prostate cancers need supplies of the male hormone testosterone to grow. Testosterone is an androgen (hormone) produced by the testes and adrenal glands. Anti-androgen medicines work by blocking testosterone receptors and preventing testosterone from attaching to these receptors found in prostate cells. Without testosterone, the cancer cells may either grow more slowly or stop growing altogether. You may hear this treatment called androgen deprivation therapy or ADT.

How to Take Enzalutamide

Enzalutamide is given as a capsule or tablet taken once a day, preferably at the same time each day, with or without food. Take the capsules or tablets whole. Do not break, open, or chew them. If they are too large for you to swallow them safely, talk to your pharmacist about smaller-sized sized tablets.

If you miss a dose at your regular dose time, take it as soon as you remember that day. If you miss your daily dose, take the prescribed dose at your regular time the next day. Do not take 2 doses at once to make up for a missed dose. 

It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.

The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These include: rifampin, carbamezapine, gemfibrozil, phenobarbital, phenytoin, rifampin, ritonavir, St John’s wort, midazolam, and warfarin. If you continue to take warfarin your INR will be closely monitored. Be sure to tell your healthcare provider about all medications and supplements you take.

Storage and Handling

Store your medication in the original, labeled container at room temperature and in a dry location (unless otherwise directed by your healthcare provider or pharmacist). This medication should not be stored in a pillbox. Keep containers out of reach of children and pets.

If a caregiver prepares your dose for you, they should consider wearing gloves or pouring manythe pills directly from their container into the cap, a small cup, or directly into your hand. They should avoid touching the pills. They should always wash their hands before and after giving you the medication. Pregnant or nursing women should not prepare the dose for you. Ask your oncology team where to return any unused medication for disposal. Do not flush down the toilet or throw it in the trash.

Where do I get this medication?

Enzalutamide is available through select specialty pharmacies. Your oncology team will work with your prescription drug plan to identify an in-network specialty pharmacy for the distribution of this medication and shipment directly to your home.

Insurance Information

This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals depending upon prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, may also be available. Your care team can help you find these resources if they are available.

Possible Side Effects of Enzalutamide

There are a number of things you can do to manage the side effects of enzalutamide. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:

Fatigue

Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team for helpful tips on dealing with this side effect.

Muscle or Joint Pain/Aches and Headache

Your healthcare provider can recommend medications and other strategies to help relieve pain.

Diarrhea

Your oncology care team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals and seeds. Soluble fiber is found in some foods and absorbs fluid, which can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange sections, boiled potatoes, white rice, products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses of non-alcoholic, un-caffeinated fluid a day to prevent dehydration.

Constipation

There are several things you can do to prevent or relieve constipation. Include fiber in your diet (fruits and vegetables), drink 8-10 glasses of non-alcoholic fluids a day, and keep active. A stool softener once or twice a day may prevent constipation. If you do not have a bowel movement for 2-3 days, you should contact your healthcare team for suggestions to relieve the constipation.

Hot Flashes

There are a few things you can do to help with hot flashes. Several medications have been shown to help with symptoms, including clonidine (a blood pressure medication), low doses of certain antidepressants (such as venlafaxine and fluoxetine), and gabapentin. Talk to your healthcare team about these prescription products to determine if they are right for you.

Non-medical recommendations include:

• Keep well-hydrated with eight glasses of water daily.
• Drink ice water or apply an ice pack at the onset of a hot flash.
• Wear cotton or lightweight, breathable fabrics and dress in layers so you can adjust as needed.
• Exercise on a regular basis.
• Try practicing meditation or relaxation exercises to manage stress, which can be a trigger.
• Avoid triggers such as warm rooms, spicy foods, caffeinated beverages, and alcohol.

Decrease in Appetite or Taste Changes

Nutrition is an important part of your care. Cancer treatment can affect your appetite and, in some cases, the side effects of treatment can make eating difficult. Ask your oncology care team about nutritional counseling services at your treatment center to help with food choices.

• Try to eat five or six small meals or snacks throughout the day, instead of 3 larger meals.
• If you are not eating enough, nutritional supplements may help.
• You may experience a metallic taste or find that food has no taste at all. You may dislike foods or beverages that you liked before receiving cancer treatment. These symptoms can last for several months or longer after treatment ends.
• Avoid any food that you think smells or tastes bad. If red meat is a problem, eat chicken, turkey, eggs, dairy products, and fish without a strong smell. Sometimes cold food has less of an odor.
• Add extra flavor to meat or fish by marinating it in sweet juices, sweet and sour sauce, or dressings. Use seasonings like basil, oregano, or rosemary to add flavor. Bacon, ham, and onion can add flavor to vegetables.

Important but Less Common Side Effects

• Seizure: In clinical trials, a very small number of patients experienced a seizure. You should avoid activities where a sudden loss of consciousness could cause serious harm to you or others. Contact your oncology team right away if you experience a seizure. You should also make your team aware if you have a history of seizures.
• Posterior Reversible Encephalopathy Syndrome (PRES): In rare cases, this medication has caused a neurological disorder called posterior reversible encephalopathy syndrome (PRES). Symptoms of PRES include headache, seizure, lethargy, confusion, blindness, and other visual and neurological disturbances. Report any of these symptoms to your healthcare team immediately.
• Hypersensitivity: ,Allergic reaction is possible. Symptoms include swelling of the face, tongue and lips. If you experience these symptoms, stop taking this medication and contact your care team immediately.
• Ischemic heart disease: Some patients taking this medication have experienced heart blockages (ischemic heart disease). Your team will monitor your heart functions throughout treatment. Contact your care team or go to the emergency room if you have chest pain/discomfort or shortness of breath.
• Increased risk of falls/fractures: This medication can increase your risk for falls and broken bones. These falls are not related to other causes like loss of consciousness, fainting, or seizures. Your team will monitor your bone health and fracture risk during treatment.
• Breast tenderness or increase in breast tissue: An increase in breast tissue (gynecomastia) or breast tenderness may develop. Your healthcare team can suggest medications to relieve the tenderness. In rare cases, radiation can be given to relieve severe tenderness.
• Weakening of the bones (Osteoporosis): People who take hormone therapy for extended periods of time are at risk for bone thinning (osteoporosis). You may be advised to take calcium and vitamin D supplements to help prevent bone loss. Weight-bearing exercise and a healthy diet rich in calcium and vitamin D can also help protect your bone health. You may have a bone density scan (DEXA scan) to assess your bone health. If your healthcare provider determines that you are at high risk of developing osteoporosis, they may recommend additional treatment with a type of medication called a bisphosphonate to help strengthen the bones.

Sexual and Reproductive Changes

This medication reduces the amount of testosterone in your body and may lead to erectile dysfunction or a decreased desire for sex during treatment. Talk to your urologist about options for treating erectile dysfunction.

Exposure of an unborn child to this medication could cause birth defects, so you should not father a child while on this medication. A condom and another form of effective birth control are necessary during treatment and for three months after you have completed treatment, even if you believe you are not producing sperm. Discuss these options with your oncology team.