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Overview: Yonsa is used for certain types of prostate cancer. Common side effects include hot flashes, diarrhea, and joint swelling or pain. Yonsa interacts with several medicines. Be sure to tell your health care provider about all of the medicines that you take. Keep all appointments to have your blood checked, as this medicine can damage your liver. Tell your health care provider right away if you get severe nausea, stomach pain, or your pee (urine) turns a brownish color.

Uses

What is Yonsa used for?

Yonsa is commonly used to treat certain types of prostate cancer.

Yonsa may also be used for other conditions as determined by your health care provider.

How does Yonsa work (mechanism of action)?

Prostate cancer cells need certain hormones, called androgens, to grow. Yonsa blocks an enzyme in the body called CYP17, which is important for making androgens. Yonsa lowers androgen levels, which can help shrink and slow the growth of prostate cancer.

How is Yonsa supplied (dosage forms)?

Brand and other names

  • Yonsa

Dosage forms and strengths

  • 125 mg oral tablets

How should I store Yonsa?

Yonsa should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Side Effects

What are the most common side effects of Yonsa?

The most common side effects of Yonsa are listed below. Side effects may vary based on the specific product you are taking. Tell your health care provider if you have any of these side effects that bother you.

There may be other side effects of Yonsa that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of Yonsa?

While less common, the most serious side effects of Yonsa are described below, along with what to do if they happen.

Severe Allergic Reactions. Yonsa may cause allergic reactions, which can be serious. Stop taking Yonsa and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Reduced Adrenal Function. Yonsa can raise the risk of adrenal insufficiency, which is when your adrenal glands make less stress hormone (cortisol) than usual. This side effect may happen if your body is under more stress than usual (because of fever, surgery, trauma, etc), or if you stop or reduce your dosage of a steroid medicine, such as prednisone. Tell your health care provider if you have any of the following symptoms of adrenal insufficiency.

  • Nausea or vomiting
  • Weakness or unusual tiredness
  • Low blood pressure

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking Yonsa. Keep all appointments to check your blood work before starting Yonsa and during and after treatment. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Low Potassium Levels. Yonsa can lead to low potassium levels (hypokalemia), which can be serious and may lead to death. Keep all appointments to have your blood checked. Call your health care provider if you have any of the following symptoms of a low potassium level.

  • Weakness
  • Unusual tiredness
  • Muscle cramps or twitching
  • Constipation
  • Heart palpitations or heart rhythm problems

Fluid Retention. Yonsa can cause fluid retention, also called edema. Fluid retention can cause serious issues in people with certain conditions, such as heart failure or kidney problems. Call your health care provider right away if you have any of the following symptoms. 

  • Chest pain
  • Irregular heartbeat
  • Shortness of breath
  • Stretched or shiny skin
  • Swollen body parts, such as the belly or ankles

Increased Blood Pressure. Yonsa may increase your blood pressure or make it worse if you already have a history of high blood pressure (hypertension). Keep all appointments to have your blood pressure checked. Increases in blood pressure may not be noticeable, but look out for and tell your health care provider right away if you have any of the following symptoms of severely high blood pressure.

  • Sudden severe headache
  • Chest pain
  • Dizziness or confusion
  • Trouble breathing
  • Nausea or vomiting
  • Blurry or other changes to vision
  • Anxiety
  • Buzzing in the ears
  • Nosebleeds
  • Feeling of skipped heartbeats

Warnings & Precautions

Who should not use Yonsa?

Allergies to Ingredients. People who are allergic to any of the following should not take Yonsa.

  • Abiraterone
  • Yonsa
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in Yonsa.

What should I know about Yonsa before using it?

Do not take Yonsa unless it has been prescribed to you by a health care provider. Take it as prescribed. Do not change your dose or stop taking Yonsa without talking to your health care provider.

Do not share Yonsa with other people, even if they have the same condition as you. It may harm them.

Keep Yonsa out of the reach of children.

Do not chew, cut, or crush Yonsa. Swallow the tablets whole with water.

Yonsa may affect your ability to get your partner pregnant. Talk with your health care provider if you have concerns about this. 

If your partner can get pregnant, you should use effective birth control (such as condoms) while you are taking Yonsa and for three weeks after your last dose. If your partner is pregnant or may become pregnant, they should not touch Yonsa tablets, especially broken tablets, without wearing gloves. See the Pregnancy section for more details. 

What should I tell my health care provider before using Yonsa?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if Yonsa is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Heart problems, such as a recent heart attack, heart failure, or other heart problems
  • High blood pressure
  • Liver problems
  • Problems with hormone glands, such as adrenal or pituitary glands

Diabetes. Yonsa may cause changes in your blood sugar levels, including increasing your risk for severely low blood sugar levels if you have diabetes. The risk may be higher if you take certain diabetes medicines. See the Interactions section for more details. Before taking Yonsa, tell your health care provider if you have diabetes. Follow any instructions from your health care provider about checking your blood sugar levels while you are taking Yonsa.

Other Medicines and Supplements. Yonsa may interact with other medicines and supplements. Before taking Yonsa, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Radiation. Tell your health care provider if you are receiving other treatments for prostate cancer. Receiving a certain radiation medicine while taking Yonsa may raise the risk of broken bones (fractures) or even death. See the Interactions section for more details.

Pregnancy. People who can become pregnant are not usually prescribed Yonsa. Yonsa can cause harm to an unborn baby. Yonsa should not be taken or touched if you are pregnant. Tell your health care provider if your partner is pregnant or plans to become pregnant.

Breastfeeding. People who can breastfeed are not usually prescribed Yonsa. It is not known if Yonsa passes into breast milk. Tell your health care provider if your partner is breastfeeding or plans to breastfeed.

Interactions

Does Yonsa interact with foods or drinks?

Yonsa may be taken with or without food.

It is unknown if drinking alcohol will affect Yonsa, but both Yonsa and alcohol can increase your risk of liver damage. It is best to limit the amount of alcohol you drink.

Does Yonsa interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are taking any of the following before taking Yonsa.

  • Any medicine for seizures, such as carbamazepine, phenytoin, or phenobarbital
  • Rifampin (Rifadin) or rifapentine (Priftin), which are commonly used to treat an infection called tuberculosis
  • Rifabutin (Mycobutin), which is a medicine used to prevent mycobacterium avium complex infection
  • Dextromethorphan, a cough suppressant that is often found in cough medicines like Delsym, Robitussin DM, and others
  • Thioridazine, which is a medicine to treat a mental health condition called schizophrenia
  • Pioglitazone (Actos), which is a medicine for diabetes
  • Repaglinide, which is a medicine for diabetes
  • Radium Ra 223 dichloride (Xofigo), which is a radiation-emitting medicine used to treat certain people with prostate cancer

Many other medicines may alter the blood levels of Yonsa and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with Yonsa. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally take too much Yonsa?

If you or someone else has taken too much Yonsa, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of Yonsa?

If you miss one dose, skip the missed dose. Take your next dose when you normally would. Do not take double or extra doses. If you miss more than one dose, contact your health care provider for instructions.