About 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. The production of testosterone can be stopped by surgically removing the testicles or through medication therapy. Anti-androgen medications (also called nonsteroidal anti-androgens) work by blocking testosterone receptors on the prostate cells, and therefore preventing testosterone from attaching to the receptors on the surface of the prostate cancer cells. Without testosterone, the cancer cells may either grow more slowly, or stop growing altogether.
How to Take Enzalutamide
Enzalutamide is given as a capsule, taken once a day, preferably at the same time each day. Take the capsule whole. Do not break, open, dissolve or chew them.
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.
The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These include: grapefruit, grapefruit juice, dexamethasone, ketoconazole, rifampin, phenytoin, St. John’s wort, and modafanil. Be sure to tell your healthcare provider about all medications and supplements you take.
Storage and Handling
Store this medication at room temperature in the original container, with the lid tightly closed. If you prefer to use a pillbox, discuss this with your oncology pharmacist. Ask your oncology team where to return any unused medication for disposal. Do not flush down the toilet or throw 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 distribution of this medication and shipment directly to your home.
This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals without prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, are also 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 doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:
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 Prozac), and gabapentin. 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.
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 doctor or nurse can recommend medication and other strategies to relieve pain.
In clinical trials, some 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.
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.
Weakening of the Bones (Osteoporosis)
Men 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 physician 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.
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.
Your oncology 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 on non-alcoholic, un-caffeinated fluid a day to prevent dehydration.
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.
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 other form of effective birth control is 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.