Abiraterone Acetate

What it is used for

Abiraterone acetate tablets are used together with prednisone to treat men with metastatic castration-resistant prostate cancer (CRPC) or metastatic high-risk castration-sensitive prostate cancer (CSPC).

How it is taken

The usual dose is 1,000 mg (two 500 mg tablets or four 250 mg tablets) taken once daily on an empty stomach. Do not eat food 2 hours before and 1 hour after taking the tablets. Swallow the tablets whole with water. Do not crush or chew. For CRPC, take with prednisone 5 mg twice daily. For CSPC, take with prednisone 5 mg once daily. You will also receive a GnRH analog or have had orchiectomy. If you have moderate liver problems, the starting dose is 250 mg once daily. If you take a strong CYP3A4 inducer, your doctor may increase the dose to 1,000 mg twice a day only during co-administration.

Warnings

• Abiraterone acetate can cause high blood pressure, low potassium, and fluid retention due to mineralocorticoid excess.
• Adrenocortical insufficiency may occur.
• Hepatotoxicity (liver damage) has been reported; monitor liver function tests. If severe liver injury occurs, treatment should be permanently stopped.
• Increased fractures and death have been seen when used with radium Ra 223 dichloride.
• Cardiac failure occurred more often in patients taking abiraterone acetate (2.6%) compared to placebo (0.9%).

Common side effects

• Fatigue
• Arthralgia (joint pain)
• Hypertension (high blood pressure)
• Nausea
• Edema (swelling)
• Hypokalemia (low potassium)
• Hot flush
• Diarrhea
• Vomiting
• Upper respiratory infection
• Cough
• Headache

Interactions

Avoid strong CYP3A4 inducers (e.g., phenytoin, carbamazepine, rifampin, rifabutin, rifapentine, phenobarbital) during treatment. If a strong CYP3A4 inducer must be used, the abiraterone dose may be increased to twice daily. Avoid co-administration with CYP2D6 substrates that have a narrow therapeutic index (e.g., thioridazine). If needed, consider dose reduction of the CYP2D6 substrate. Monitor for toxicity if using CYP2C8 substrates with a narrow therapeutic index.