XTANDI contains the active ingredient enzalutamide, which is an androgen receptor inhibitor. It is available in liquid-filled soft gelatin capsules containing 40 mg of enzalutamide and in film-coated tablets with 40 mg or 80 mg of enzalutamide, both for oral administration. Key inactive ingredients include caprylocaproyl polyoxylglycerides, gelatin, and titanium dioxide in the capsules, and hypromellose and microcrystalline cellulose in the tablets.

How should I use this medication?

Take this medication by mouth. Take it as directed on the prescription label at the same time every day. Do not cut, crush, or chew this medication. Swallow the tablets whole. You can take it with or without food. If it upsets your stomach, take it with food. Keep taking it unless your care team tells you to stop. Talk to your care team about the use of this medication in children. Special care may be needed.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once. NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medication?

Keep out of the reach of children and pets. Store between 20 and 25 degrees C (68 and 77 degrees F). Protect from moisture. Keep the container tightly closed. Get rid of any unused medication after the expiration date. To get rid of medications that are no longer needed or have expired: -Take the medication to a medication take-back program. Check with your pharmacy or law enforcement to find a location. -If you cannot return the medication, check the label or package insert to see if the medication should be thrown out in the garbage or flushed down the toilet. If you are not sure, ask your care team. If it is safe to put it in the trash, empty the medication out of the container. Mix the medication with cat litter, dirt, coffee grounds, or other unwanted substance. Seal the mixture in a bag or container. Put it in the trash.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible: -Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat -Heart attack—pain or tightness in the chest, shoulders, arms, or jaw, nausea, shortness of breath, cold or clammy skin, feeling faint or lightheaded -Loss of balance or coordination -Seizures -Sudden and severe headache, confusion, change in vision, seizures, which may be signs of posterior reversible encephalopathy syndrome (PRES) Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome): -Back pain -Constipation -Diarrhea -Hot flashes -Increase in blood pressure -Loss of appetite -Unusual weakness or fatigue

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What should I tell my care team before I take this medication?

They need to know if you have any of these conditions: -Bone problems -Brain tumor -Head injury -Heart disease -High blood pressure -High cholesterol -Seizures -Stroke -An unusual or allergic reaction to enzalutamide, other medications, foods, dyes, or preservatives -If you or your partner is pregnant or trying to get pregnant -Breast-feeding

What may interact with this medication?

Do not take this medication with any of the following: -Artemether -Certain antivirals for HIV or hepatitis, such as atazanavir, daclatasvir, doravirine, elbasvir, fostemsavir, grazoprevir, lopinavir, nelfinavir, paritaprevir, rilpivirine, ritonavir, tipranavir -Certain medications for fungal infections, such as isavuconazonium, voriconazole -Lonafarnib -Lorlatinib -Lurasidone -Praziquantel -Ranolazine This medication may also interact with the following: -Alfentanil -Certain medications for seizures, such as carbamazepine, phenobarbital, phenytoin -Clopidogrel -Cyclosporine -Ergot alkaloids, such as dihydroergotamine, ergotamine -Fentanyl -Gemfibrozil -Midazolam -Omeprazole -Pimozide -Quinidine -Rifabutin -Rifampin -Rifapentine -Sirolimus -St. John's wort -Tacrolimus -Warfarin

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medication?

Your condition will be monitored carefully while you are receiving this medication. Talk to your care team if you or your partner are pregnant or think either of you might be pregnant. This medication can cause serious birth defects. If your partner can get pregnant, use a condom during sex while taking this medication and for 3 months after the last dose. This medication may cause infertility. Talk to your care team if you are concerned about your fertility.