Abiraterone

Name: Abiraterone

What Is Zytiga (Abiraterone)?

Zytiga is the brand name of the prescription drug abiraterone acetate, which is used along with the drug prednisone to treat prostate cancer that has spread to other areas of the body.

The medicine is given to men who can't be treated with surgery or other therapies.

Zytiga belongs to a class of drugs called androgen biosynthesis inhibitors. It works by reducing the levels of certain hormones in the body.

The U.S. Food and Drug Administration (FDA) approved Zytiga in 2011. It's manufactured by Janssen Biotech, Inc.

Zytiga Warnings

Before taking Zytiga, tell your doctor if you have, or have ever had:

  • Liver disease
  • Low potassium in your blood
  • Any type of infection
  • High blood pressure
  • Congestive heart failure or heart disease
  • An irregular heartbeat
  • A recent heart attack
  • Fluid retention
  • Problems with your adrenal gland or pituitary gland
  • Allergies to medications

Zytiga should only be taken by men. Women and children (under 18) shouldn't take this drug.

Continue to take this medicine even if you feel well. Don't stop taking Zytiga without first talking to your doctor.

Your healthcare provider will want to check your blood pressure often while you're taking Zytiga. You may also need frequent blood tests. Keep all appointments with your doctor's office and laboratory.

Zytiga can pass into bodily fluids such as urine, vomit, and feces. Wear protective gloves while handling or cleaning up any of these fluids, and be sure to wash your hands before and after doing this.

Pregnancy and Zytiga

Although women don't take Zytiga, simply touching the medicine may harm an unborn baby.

Pregnant women, and those who may become pregnant, shouldn't handle Zytiga tablets without wearing protective gloves.

If a pregnant woman touches or accidentally takes a Zytiga tablet, she should call her doctor immediately.

If a man taking Zytiga has sex with a woman who could become pregnant, the couple should use a condom and another form of effective birth control.

Continue taking this precaution for one week after treatment with Zytiga ends.

If a man has sex with a pregnant woman while taking Zytiga, he should use a condom to avoid transferring the medicine.

This precaution should also be continued for one week after treatment with Zytiga ends.

Zytiga Side Effects

Common Side Effects of Zytiga

Tell your doctor if any of the following side effects become severe or don't go away:

  • Joint pain or swelling
  • Hot flashes
  • Heartburn
  • Diarrhea
  • Coughing

Serious Side Effects of Zytiga

Tell your doctor immediately if you experience any of the following serious side effects:

  • Dizziness, lightheadedness, or faintness
  • Headache
  • Confusion
  • Fast or irregular heartbeat
  • Muscle aches or weakness
  • Leg pain
  • Unusual bleeding or bruising
  • Swelling of the hands, feet, ankles, or lower legs
  • Extreme tiredness or lack of energy
  • Nausea
  • Loss of appetite
  • Pain in the upper right part of the stomach
  • Yellowing of the skin or eyes
  • Flu-like symptoms
  • Painful, difficult, or frequent urination

Why is this medication prescribed?

Abiraterone is used in combination with another medication (prednisone) to treat prostate cancer that has spread to other parts of the body in men who have not been helped by other treatments including docetaxel (Docefrez, Taxotere). Abiraterone is in a class of medications called androgen biosynthesis inhibitors. It works by decreasing the amount of certain hormones in the body.

Brand names

  • Zytiga®

Abiraterone Overview

Abiraterone is a prescription medication used to treat prostate cancer that has spread to other parts of the body. Abiraterone belongs to a group of drugs called CYP17 inhibitors, which work by decreasing the amount of testosterone in the body. Testosterone stimulates prostate cancer cells to grow.

This medication comes in tablet form and is taken once a day without food, on an empty stomach. Do not take abiraterone with food as food may cause more of the medicine to be absorbed by the body than is needed. Do not eat 2 hours before taking abiraterone and do not eat 1 hour after taking abiraterone. 

Take abiraterone with water. 

Swallow abiraterone tablets whole. Do not crush or chew abiraterone tablets.

Common side effects of abiraterone include joint swelling or pain, muscle aches, hot flushes, and diarrhea.

Abiraterone Brand Names

Abiraterone may be found in some form under the following brand names:

  • Zytiga

Abiraterone Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • antifungal medicines such as itraconazole (Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend)
  • clarithromycin (Biaxin, in Prevpac)
  • HIV protease inhibitors including atazanavir (Reyataz), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Fortovase, Invirase)
  • carbamazepine (Carbatrol, Epitol, Tegretol)
  • phenobarbital (Luminal)
  • phenytoin (Dilantin, Phenytek)
  • nefazodone (Serzone)
  • rifabutin (Mycobutin)
  • rifampin (Rifadin, in Rifamate, in Rifater, Rimactane)
  • rifapentine (Priftin)
  • telithromycin (Ketek)
  • thioridazine (Mellaril)
  • nimodipine (Nimotop)
  • St. John's wort

This is not a complete list of abiraterone drug interactions. Ask your doctor or pharmacist for more information.

Dosing & Uses

Dosage Forms & Strengths

tablet

  • 250mg
  • 500mg

Prostate Cancer

Indicated for treatment of metastatic castration-resistant prostate cancer (CRPC) in patients who are chemotherapy-naive or in those who have received prior chemotherapy containing docetaxel; administer with prednisone

1000 mg PO qDay with prednisone 5 mg PO q12hr

Dosage Modifications

Strong CYP3A4 inducers

  • Coadministration with strong CYP3A4 inducers: Avoid if possible; if must be coadministered, increase dosage frequency of abiraterone from qDay to BID (eg, from 1,000 mg qDay to 1,000 mg BID)
  • Reduce the dose back to the previous dose and frequency, if the concomitant strong CYP3A4 inducer is discontinued

Hepatic impairment

  • Baseline LFTs
    • Mild (Child-Pugh A): Dose adjustment not required
    • Moderate (Child-Pugh B): Reduce starting dose to 250 mg PO qDay
    • Severe (Child-Pugh C): Avoid use; not studied in this population and no dose adjustment can be predicted
  • Increased LFTs during treatment
    • Interrupt treatment; may reinitiate at reduced dose of 750 mg PO qDay following return of LFTs to baseline or to AST/ALT ≤2.5 xULN and total bilirubin ≤1.5 xULN
    • For patients who resume treatment, monitor serum transaminases and bilirubin at least q2Weeks for 3 months, and then monthly thereafter
    • If hepatotoxicity recurs at 750 mg/day, may restart at 500 mg/day (after LFTs decrease as above)
    • If hepatoxicity recurs at reduced dose of 500 mg/day, discontinue treatment

Renal impairment

  • Dose adjustment not required

Safety and efficacy not established

Prostate Cancer

Indicated for treatment of metastatic castration-resistant prostate cancer (CRPC) in patients who are chemotherapy-naive or in those who have received prior chemotherapy containing docetaxel; administer with prednisone

1000 mg PO qDay with prednisone 5 mg PO q12hr

Of the total number of patients in a phase 3 trial, 71% of patients were 65 yr or older and 28% were 75 yr or older

No overall differences in safety or effectiveness were observed between these elderly patients and younger patients

Pregnancy & Lactation

Pregnancy Category: X

Lactation: Unknown whether distributed in breast milk; do not use, not indicated for use in women

Pregnancy Categories

A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA:Information not available.

Precautions

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

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