Abiraterone and niraparib is a combination medicine used together with prednisone in adults to treat prostate cancer that has spread to other parts of the body (metastatic) and cannot be treated with surgery.

Abiraterone and niraparib is used only if your cancer has a specific genetic marker (an abnormal "BRCA" gene) or other gene mutations. Your doctor will make sure you have the correct tumor type to be treated with abiraterone and niraparib.

Abiraterone and niraparib is not for use by women or children.

Abiraterone and niraparib may also be used for purposes not listed in this medication guide.

Abiraterone and niraparib may increase your risk of developing serious bone marrow problems or other types of cancer, such as leukemia. Ask your doctor about your individual risk.

Tell your doctor if you have or have ever had:

• diabetes;
• heart problems, high blood pressure;
• low levels of potassium in your blood;
• problems with your adrenal gland; or
• liver or kidney disease.

Abiraterone and niraparib can cause miscarriage and harm an unborn baby if a woman is exposed to this medicine during pregnancy. An abiraterone and niraparib tablet should be handled with protection (gloves) by a woman who is pregnant or may become pregnant.

Use birth control if your sex partner is able to get pregnant. Keep using birth control for at least 4 months after your last dose.

Use Abiraterone And Niraparib (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• swelling in your hands, ankles, legs or feet;
• pain in your legs;
• fast or irregular heartbeats;
• weight loss, dizziness, feeling tired or light-headed, like you might pass out;
• headache, confusion, thinking problems, weakness, vision loss, seizure;
• low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;
• low blood potassium--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling;
• liver problems--stomach pain (upper right side), nausea, vomiting, dark urine, jaundice (yellowing of the skin or eyes); or
• low blood sugar--headache, hunger, weakness, sweating, confusion, irritability, dizziness, fast heart rate, or feeling jittery.

Your abiraterone and niraparib treatments may change, be delayed, or permanently discontinued if you have certain side effects.

Common side effects may include:

• muscle and bone pain, feeling very weak or tired;
• easy bruising or bleeding;
• loss of appetite, weight loss;
• irregular heartbeats, increased blood pressure;
• swelling in your legs or feet;
• pain and burning when you urinate, painful urination;
• abnormal liver function tests or other blood tests;
• trouble sleeping;
• shortness of breath, dizziness, falls, headache;
• stomach pain, nausea, vomiting, constipation; or
• COVID-19 or cold symptoms such as fever, stuffy nose, sneezing, cough, sore throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.