What is Yonsa and how does it work?

Yonsa (abiraterone acetate) is a prescription medicine used with methylprednisolone to treat prostate cancer that has spread to other parts of the body and no longer responds to medical or surgical treatment that lowers testosterone.

Do not take Yonsa if you:

  • are pregnant or may become pregnant. Yonsa may harm your unborn baby.
  • are female.

Yonsa is not for use in women.

What are the side effects of Yonsa?

Yonsa may cause serious side effects, including:

  • High blood pressure (hypertension), low blood potassium levels (hypokalemia) and fluid retention (edema). Tell your healthcare provider if you get any of the following symptoms:
  • Adrenal problems may happen if you stop taking methylprednisolone, get an infection, or are under stress.
  • Liver problems. You may develop changes in liver function blood tests. Your healthcare provider will do blood tests to check your liver before treatment with Yonsa and during treatment with Yonsa. Liver failure may occur, which can lead to death. Tell your healthcare provider if you notice any of the following changes:
    • yellowing of the skin or eyes
    • darkening of the urine
    • severe nausea or vomiting

The most common side effects of Yonsa include:

Yonsa may affect fertility in males and may affect your ability to father a child. Talk to your healthcare provider if this is a concern for you.

These are not all the possible side effects of Yonsa.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the dosage for Yonsa?

  • Take Yonsa and methylprednisolone exactly as your healthcare provider tells you.
  • Take your prescribed dose of Yonsa 1 time a day. Take your prescribed dose of methylprednisolone 2 times a day.
  • Yonsa contains abiraterone acetate. Yonsa and other medicines that contain abiraterone acetate may not be the same.
    • Do not switch between Yonsa and other medicines that contain abiraterone acetate unless your healthcare provider tells you to.
    • Follow your healthcare provider’s instructions carefully if you are switching between Yonsa and another medicine that contains abiraterone acetate.
    • Do not take Yonsa and other medicines that contain abiraterone acetate on the same day.
    • If you do not have enough Yonsa to take your full dose or if you have any other questions about Yonsa, talk with your healthcare provider or pharmacist.
  • Your healthcare provider may change your dose of Yonsa if needed.
  • Do not stop taking your prescribed dose of Yonsa or methylprednisolone without talking with your healthcare provider first.
  • Take Yonsa with or without food.
  • Swallow Yonsa tablets whole with water. Do not crush or chew tablets.
  • If you miss a dose of Yonsa or methylprednisolone, take your prescribed dose the following day. If you miss more than 1 dose, tell your healthcare provider right away.
  • If you are receiving gonadotropin-releasing hormone (GnRH) therapy, you should continue your therapy during treatment with Yonsa and methylprednisolone.
  • If you take too much Yonsa, call your healthcare provider or go to the nearest hospital emergency room right away.
  • Your healthcare provider will do blood tests to check for side effects.


Prostate Illustrion Browse through our medical image collection to see illustrations of human anatomy and physiology See Images

What drugs interact with Yonsa?

Drugs That Inhibit Of Induce CYP3A4 Enzymes

Based on in vitro data, Yonsa is a substrate of CYP3A4.

In a dedicated drug interaction trial, co-administration of rifampin, a strong CYP3A4 inducer, decreased exposure of abiraterone by 55%. Avoid concomitant strong CYP3A4 inducers during Yonsa treatment. If a strong CYP3A4 inducer must be co-administered, increase the Yonsa dosing frequency.

In a dedicated drug interaction trial, co-administration of ketoconazole, a strong inhibitor of CYP3A4, had no clinically meaningful effect on the pharmacokinetics of abiraterone.

Effects Of Abiraterone On Drug Metabolizing Enzymes

Abiraterone is an inhibitor of the hepatic drug-metabolizing enzymes CYP2D6 and CYP2C8. In a CYP2D6 drug-drug interaction trial, the Cmax and AUC of dextromethorphan (CYP2D6 substrate) were increased 2.8and 2.9-fold, respectively, when dextromethorphan was given with an abiraterone acetate dose equivalent to Yonsa 500 mg daily and a different corticosteroid twice daily. Avoid coadministration of abiraterone acetate with substrates of CYP2D6 with a narrow therapeutic index (e.g., thioridazine). If alternative treatments cannot be used, exercise caution and consider a dose reduction of the concomitant CYP2D6 substrate drug.

In a CYP2C8 drug-drug interaction trial in healthy subjects, the AUC of pioglitazone (CYP2C8 substrate) was increased by 46% when pioglitazone was given together with an abiraterone acetate single dose equivalent to Yonsa 500 mg. Therefore, patients should be monitored closely for signs of toxicity related to a CYP2C8 substrate with a narrow therapeutic index if used concomitantly with abiraterone acetate.

Is Yonsa safe to take while pregnant or breastfeeding?

Based on findings from animal studies and the mechanism of action, Yonsa is contraindicated for use in pregnant women because the drug can cause fetal harm and potential loss of pregnancy. Yonsa is not indicated for use in females.

There is no information available on the presence of Yonsa in human milk, the effects of the drug on the breastfed infant, or the effects of the drug on milk production.

Women who are pregnant or who may become pregnant should not touch Yonsa tablets if broken, crushed, or damaged without protection, such as gloves.

  • Men who are sexually active with a woman who may become pregnant must use effective birth control during treatment and for at least 3 weeks after the final dose of Yonsa.
  • Men who are sexually active with a woman who is pregnant must use a condom.


Screening Tests Every Man Should Have See Slideshow


Yonsa (abiraterone acetate) is a drug to treat metastatic prostate cancer in men. Women should not ever take or even handle the drug, especially if pregnant. It's meant to be used methylprednisolone.

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