Xtandi (Enzalutamide): What It Is, How It Works, and What To Expect

What Is Xtandi?

Enzalutamide (pronounced [en za LOO ta mide]) is also known by the brand name Xtandi. In the United States, there is currently no generic version of Xtandi available. Xtandi is an antineoplastic (anti-cancer) medication that belongs to a class called androgen receptor inhibitors (antiandrogens). It is used as hormonal (endocrine) therapy for certain types of prostate cancer and is not considered traditional cytotoxic chemotherapy.

What Is Hormonal (Endocrine) Therapy for Prostate Cancer?

Hormonal (endocrine) therapy for prostate cancer works by blocking the effect of androgens (male hormones such as testosterone) that can help prostate cancer grow. Xtandi is an androgen receptor inhibitor that helps prevent androgens from activating the androgen receptor and can slow the growth of prostate cancer.

Safe Handling Precautions

Xtandi is considered a hazardous medication. Do not crush, chew, break, or open the capsules or tablets. If a capsule or tablet is damaged, avoid direct contact with the contents; wash the area with soap and water if contact occurs. If handling damaged medication is necessary, use gloves and follow your workplace/provider instructions for safe handling and disposal.

How Is Xtandi Used?

Xtandi has been approved by the Food and Drug Administration (FDA) to treat different types of prostate cancers. It may be prescribed alone or in combination with other prostate cancer treatments (for example, androgen deprivation therapy and other agents), depending on the type of prostate cancer and prior treatment history.

Available Formulations

Xtandi is only available in the form of capsules or tablets and must be administered orally. The tablets are available in two different strengths: 40 mg and 80 mg. The capsules are only available in 40 mg strength. The 40 mg round and 80 mg elliptical tablets are yellow and stamped with “E 40” and “E 80,” respectively. The 40 mg capsules are white and stamped with either “MDV” or “ENZ” on one side. The capsules contain an additional ingredient, sorbitol. Tablet/capsule appearance and markings may vary by manufacturer or packaging; verify your product using the pharmacy label and pharmacist guidance.

Directions for Use

Xtandi may be taken without regard to food. It should be taken at the same time each day. While taking the capsule or tablet, swallow it whole; do not break, crush, chew, or allow it to be dissolved in your mouth. Xtandi is typically dosed once a day, and the dose is dependent on the cancer type and severity. Verify the correct dose and frequency with your provider. The dose should not be more or less than what is prescribed. 

Missed Dose

If you accidentally miss a dose, take your prescribed dose as soon as you remember that day. If you missed your dose for the day, take your prescribed dose at the regular time the next day. Do not take more than your prescribed dose of Xtandi each day.

Storage

Store Xtandi in a cool, dry place at room temperature and ensure the bottle is tightly closed.

What To Avoid While Taking Xtandi

While receiving Xtandi, you must follow some precautions. Always tell your physician about any medication you are already taking. Do not start or stop any prescription, over-the-counter, vitamin, or herbal product without prior consent from your physician or pharmacist, as they may have some significant interactions with Xtandi.

Pregnancy and Xtandi

Xtandi may cause fetal harm and/or loss of pregnancy (miscarriage). Male patients with female partners of childbearing age should use effective contraception during treatment and for 3 months after the last dose. 

Side Effects

As with any other medication, you may encounter side effects while taking Xtandi. A few things to remember are:

• You may not have all the side effects listed below. Many people may experience little to no side effects.
• The severity of side effects may vary from person to person, so don’t compare your side effects with other people’s experiences.
• Most of the side effects will improve when therapy is discontinued.
• These side effects are often manageable, sometimes by adjusting the dose or schedule, or by using additional medications to help treat symptoms (as directed by your provider). Consult with your physician or pharmacist to explore available options.
• Do not hide any symptoms; when you feel any discomfort, do not hesitate to tell your physician or pharmacist about it.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions. 

Some of the most common side effects of Xtandi are:

Cardiac Complications

Xtandi may increase blood pressure or worsen preexisting hypertension. Symptoms of high blood pressure can include a severe headache, dizziness, fainting, or changes in vision. Your healthcare team may recommend monitoring blood pressure and treating elevated readings if needed. Serious cardiovascular or clotting events are uncommon but can occur, especially in patients with underlying risk factors — seek medical attention right away for chest pain, shortness of breath, sudden weakness, or trouble speaking.

Hormonal Side Effects

Because Xtandi affects androgen, a hormone, it may cause a hormonal imbalance in the body, resulting in side effects like hot flashes, fatigue/weakness, back or joint/muscle pain, lack of appetite, weight loss, and trouble sleeping.

Allergic Reactions

Allergic reactions can be another side effect of Xtandi. A mild allergic reaction can include a rash on the skin, skin becoming itchy, etc. Severe side effects may include swelling under the eyes, lips, or hands; and swelling of the throat or tongue with disturbed breathing. Immediately contact your physician if any signs of an allergic reaction are present. If a severe reaction occurs, discontinuation of Xtandi may be recommended. 

Fall or Fracture Risk

Patients who have a high fracture or fall risk may need to consider taking additional therapy that can help increase bone density to prevent any falls or bone fractures. This risk is potentially due to the high chance of fatigue and weakness/dizziness.

Infertility

There is a risk that Xtandi may impair fertility in males of reproductive potential.

Other common side effects may include:

• Constipation or diarrhea
• Common cold symptoms
• Change in taste
• Anxiety

Precautions

Unless approved by your physician, Xtandi is generally not recommended in: 

• Patients with risk of cardiovascular events. These events can include a history of heart disease, high blood pressure, abnormal amounts of fat or cholesterol in the blood (dyslipidemia), history of heart attack or stroke, etc. Xtandi is known for potentially increasing blood pressure, leading to an increased risk of cardiovascular events taking place. If any of these events occur, discontinuation or a decrease in dose may be warranted. 
• Patients with posterior reversible encephalopathy syndrome (PRES). PRES is a neurological disorder and may present as headache, seizure, lethargy, confusion, blindness, and other visual/neurologic symptoms with possible hypertension. Diagnosis of PRES can be confirmed by MRI, and if confirmed, it is recommended to discontinue Xtandi immediately.
• Patients with a history of seizures, brain injury, stroke, or brain tumors. If seizures develop during treatment, it is recommended to discontinue Xtandi immediately.

FAQs

Is Xtandi a chemo agent?

Xtandi is not traditional cytotoxic chemotherapy. It is an androgen receptor inhibitor (a type of hormonal/endocrine therapy) used to treat certain types of prostate cancer by blocking androgen signaling that can help prostate cancer grow.

How should Xtandi be taken?

Xtandi may be taken without regard to food and should be taken at the same time each day. When taking the pill, swallow it whole; do not break, crush, chew, or allow it to be dissolved in your mouth. Xtandi is typically dosed once a day, and the dose is dependent on the cancer type and severity. Verify the correct dose and frequency with your provider. The dose should not be more or less than what is prescribed. 

Can you touch Xtandi?

Xtandi is considered a hazardous medication. Swallow tablets/capsules whole and do not crush or open them. If a capsule or tablet is damaged, avoid touching it directly; use gloves if handling is necessary and follow safe disposal instructions from your pharmacy or healthcare team.