Zytiga (abiraterone acetate) is a prescription drug used to treat certain forms of metastatic prostate cancer. The drug comes as an oral tablet that’s usually taken once daily.
Zytiga is used in adults to treat metastatic prostate cancer that:
- keeps spreading despite medications or surgery to reduce testosterone levels
- is managed by testosterone levels being reduced, but still needs aggressive treatment because it’s expected to spread quickly
You’ll take Zytiga together with prednisone. You may also be prescribed a gonadotropin-releasing hormone (GnRH) analog while taking Zytiga. But if you’ve had both testicles removed, you won’t need to take a GnRH analog.
The active ingredient in Zytiga is abiraterone acetate. (An active ingredient is what makes a drug work.) Zytiga belongs to a group of drugs called CYP17 inhibitors.
This article describes the dosages of Zytiga, as well as its strengths and how to take it. To learn more about Zytiga, see this in-depth article.
The table below highlights the basics of Zytiga’s dosage. All doses are listed in milligrams (mg).
| Use | Usual dosage |
| for metastatic prostate cancer that keeps spreading despite medications or surgery to reduce testosterone levels | 1,000 mg once per day with 5 mg prednisone twice daily |
| for metastatic prostate cancer that’s managed by testosterone levels being reduced but still needs aggressive treatment because it’s expected to spread quickly | 1,000 mg once per day with 5 mg prednisone once daily |
Keep reading for more details about Zytiga’s dosage.
What are Zytiga’s forms?
Zytiga comes in two oral forms: an uncoated tablet and a film-coated tablet.
What strengths does Zytiga come in?
Zytiga comes in two strengths: 250 mg and 500 mg.
The 250-mg tablet is uncoated. The 500-mg tablet is film-coated.
What are the usual dosages of Zytiga?
The information below describes dosages that are commonly prescribed or recommended. But be sure to follow the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.
Dosage for metastatic castration-resistant prostate cancer
The usual Zytiga dosage for adults with metastatic prostate cancer that continues to spread despite medications or surgery to reduce testosterone levels is 1,000 mg once daily. You’ll take this with 5 mg prednisone twice per day.
Your doctor may prescribe your dosage to be taken as two 500-mg tablets or four 250-mg tablets.
You’ll also take a GnRH analog while taking Zytiga. But if you’ve had both testicles surgically removed, your doctor likely won’t prescribe a GnRH analog with Zytiga.
Dosage for metastatic high risk castration-sensitive prostate cancer
The usual Zytiga dosage for adults with metastatic prostate cancer that still needs treatment despite being managed by reduced testosterone levels because it’s expected to spread quickly is 1,000 mg once daily. You’ll take this with 5 mg prednisone once per day.
Your doctor may prescribe your dosage to be taken as two 500-mg tablets or four 250-mg tablets.
You’ll also take a GnRH analog while taking Zytiga. But if you’ve had both testicles surgically removed, your doctor likely won’t prescribe a GnRH analog with Zytiga.
Is Zytiga taken long term?
It may be. If you and your doctor determine that it’s safe and effective for your condition, you may take Zytiga long term.
Dosage adjustments
If you have moderate liver problems before starting Zytiga, your doctor will likely prescribe a reduced dosage. But if you have severe liver problems, your doctor will likely recommend a different treatment option.
If you develop liver problems while taking Zytiga, your doctor may have you stop taking the drug until your liver recovers. If they have you restart Zytiga, they may prescribe a lower dose than you were taking before. If you continue to experience liver problems with a lower dose, your doctor may further reduce your dose or have you stop treatment completely.
Your doctor will order blood tests to monitor your liver function throughout your treatment with Zytiga to make sure your dosage is right for you.
Certain drugs, such as carbamazepine and rifampin, can greatly speed up the cytochrome P450 3A4 (CYP3A4) enzyme. This enzyme works in the liver to break down certain drugs. If you must take one of these drugs while taking Zytiga, your dosage of Zytiga will likely be increased.
If you’re receiving a type of radiation (radium Ra 223 dichloride), your doctor will likely recommend you not take Zytiga.
If you have adrenal glands that aren’t as active as they should be, your doctor may recommend an increased dose of prednisone before, during, or after situations you may find stressful.
The dosage of Zytiga you’re prescribed may depend on several factors. These include:
- the type and severity of the condition you’re taking the drug to treat
- your age
- the form of Zytiga you’re taking
- other medications you take
- other conditions you may have (see the “Dosage adjustments” section above)
Zytiga comes as an oral tablet that must be swallowed whole. It should not be crushed or chewed. If you have difficulty swallowing tablets, see this article for tips on how to take this form of medication.
If your doctor has prescribed a dosage that’s supplied in multiple tablets, take them all at once.
You’ll take your dosage on an empty stomach. Do not eat anything 2 hours before or 1 hour after taking Zytiga.
For information on the expiration, storage, and disposal of Zytiga, talk with your doctor or pharmacist.
Accessible drug containers and labels
Some pharmacies provide medication labels that:
- have large print
- use braille
- feature a code you can scan with a smartphone to change the text to audio
Your doctor or pharmacist may be able to recommend pharmacies that offer these accessibility features if your current pharmacy doesn’t.
Let your pharmacist know if you have difficulty opening medication bottles. They may have tips to help, or they may be able to supply Zytiga in an easy-open container.
If you miss a dose of Zytiga, you should take your usual dose the following day. But if you’ve missed more than one dose, contact your doctor for instructions.
If you’re not sure whether you should take a missed dose, talk with your doctor or pharmacist.
If you need help remembering to take your dose of Zytiga on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.
Do not take more Zytiga than your doctor prescribes, as this can lead to harmful effects.
What to do in case you take too much Zytiga
Call your doctor right away if you think you’ve taken too much Zytiga. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.
Below are answers to some commonly asked questions about Zytiga’s dosage.
Is Zytiga’s dosage similar to that of Xtandi?
Zytiga and Xtandi (enzalutamide) are both oral tablets taken once per day. But Xtandi also comes in oral capsules.
Zytiga is usually taken together with prednisone, while Xtandi usually isn’t. Your doctor may also prescribe another drug called a GnRH analog with either Zytiga or Xtandi. This will depend on the type of prostate cancer you have and whether your testicles have been surgically removed.
The dose in mg for each drug differs. Your doctor will prescribe the drug and dosage that’s right for you.
To learn more about how these drugs compare, talk with your doctor.
How long does it take for Zytiga to start working?
Zytiga starts to work after your first dose. Because of how the drug works, you likely won’t feel it working in your body, but you may experience side effects. Your doctor will monitor you during treatment to check whether the drug is effectively treating your condition.
If you have other questions about what to expect from your Zytiga treatment, talk with your doctor.
The sections above describe the usual dosages provided by the manufacturer of Zytiga. If your doctor recommends this drug, they’ll prescribe the dosage that’s right for you.
Remember, you should not change your dosage of Zytiga without your doctor’s recommendation. Only take this medication exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage. Here are some examples of questions you may want to ask them:
- Can I take another corticosteroid (other than prednisone) with Zytiga?
- Do I keep taking the other medications for prostate cancer I was prescribed before I started Zytiga?
- What treatment options do I have if liver problems keep me from taking Zytiga?
To learn more about Zytiga, see these articles:
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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.