What Is Abiraterone (Zytiga)?

Overview

Zytiga (abiraterone) is a CYP17 inhibitor that is used in combination with prednisone. It is indicated for use in individuals with metastatic castration-resistant prostate cancer. It is also approved with prednisone, for metastatic high-risk castration-sensitive prostate cancer (CSPC). Zytiga is a tablet taken once daily, and the prednisone accompanying it is typically taken twice daily. Individuals taking Zytiga should also be monitored for changes in the amount of mineralocorticoids and adrenocorticoids (steroid hormones) in their blood while on the medication, as well as for any signs of changes in liver functioning.

What are the ingredients in Zytiga?

The active ingredient in Zytiga is abiraterone acetate, the CYP17 inhibitor.

How does Zytiga work?

Zytiga’s active ingredient is a CYP17 inhibitor. Prostate cancer tumors are often fueled to grow by androgens, including testosterone. Turning off the body’s ability to produce testosterone, or reducing the amount made can potentially halt tumor growth. When the cancer is not responding to treatment with androgen receptor antagonists or other first-line androgen deprivation therapies, the cancer is said to be castrate-resistant. Medications like Zytiga act in different ways, like inhibiting CYP17, to decrease the production of testosterone and other circulating androgens, in attempts to stop the cancer’s growth. CYP17 is an enzyme critical in the pathways involved in producing androgens, like testosterone, as well as other essential molecules in the body, including mineralocorticoids and glucocorticoids. When the pathway to making testosterone and other androgens is blocked, tumor growth may be suppressed.

What are the possible side effects of Zytiga?

Multiple clinical trials evaluated the safety and efficacy of Zytiga. The most common side effects of Zytiga joint swelling or discomfort, muscle discomfort, fluid retention (edema), hot flashes, diarrhea, urinary tract infection, high blood pressure, cough, upper respiratory tract infection, gastrointestinal distress, and an increase in urinary frequency, including at night. This is not an exhaustive list of all potential side effects of Zytiga. Talk to your healthcare provider or pharmacist for further information.

Things to note about Zytiga

Several rare but more serious side effects can accompany Zytiga including problems with your adrenal glands (glands that assist in hormone production) and liver problems. Individuals should be closely monitored for signs of these serious side effects. Additionally, Zytiga could cause other serious side effects including low blood potassium levels, high blood sugar, sodium, and cholesterol levels, fluid retention (edema), and high blood pressure. Alert your provider immediately if you notice any of the following symptoms:

  • Fast heartbeat
  • Feeling lightheaded or faint
  • Confusion
  • Headache
  • Dizziness
  • Pain or swelling in your legs or feet
  • Muscle weakness
  • Yellowing of the skin or whites of eyes (jaundice)
  • Brown urine
  • Severe nausea or vomiting

You should also contact your provider if you notice any signs of an allergic reaction to the medication, including chest pain or difficulty breathing. It is also important to consult the prescribing information for any other medications taken with Zytiga, including prednisone.

Before staring Zytiga talk to your provider if you:

  • Have any heart problems
  • Have kidney, adrenal, pituitary, or liver problems
  • Have any other medical conditions
  • Are currently taking any other medications, vitamins, or herbal supplements

Dosing information

Zytiga is administered orally and in combination with prednisone. Typically, Zytiga is taken once daily, and prednisone twice daily. Your provider will determine the appropriate dosage and administration schedule for you. It is important to follow this schedule exactly as instructed, and not to stop taking Zytiga or prednisone on your own. Zytiga is not to be taken with food, and needs to be taken on an empty stomach. You can drink water with your Zytiga, however, no food should be eaten 2 hours prior, or 1 hour after taking Zytiga. Men who are sexually active with pregnant women or women who may become pregnant should use appropriate contraceptive methods during treatment with Zytiga and for one week after stopping Zytiga.1

Written by: Casey Hribar | Last reviewed: October 2017
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