AbirateroneAbiraterone Acetate

About Abiraterone

Abiraterone blocks CYP17, an enzyme the body needs to make androgens such as testosterone in the testes, adrenal glands and the tumor itself. The label approves it, with prednisone, for metastatic castration-resistant prostate cancer and for metastatic high-risk castration-sensitive prostate cancer, in men who are also receiving a GnRH analog or have had both testes removed. The dose is 1,000 mg once a day (two 500 mg or four 250 mg tablets) with prednisone 5 mg twice a day for castration-resistant disease or 5 mg once a day for castration-sensitive disease. It is taken on an empty stomach, with no food for two hours before and one hour after, and the tablets are swallowed whole with water. The starting dose is lowered to 250 mg a day in moderate liver impairment, and the drug is not used in severe liver impairment.

There is no boxed warning. Because abiraterone raises mineralocorticoid hormones, high blood pressure, low potassium and fluid retention are common, so blood pressure, potassium and swelling are checked at least monthly. Adrenal insufficiency can appear if prednisone is interrupted or during illness or surgery. Liver injury can be severe, so liver blood tests are done before starting, every two weeks for the first three months and monthly after that, with the dose interrupted and lowered if they rise. Low blood sugar has occurred in people taking pioglitazone or repaglinide. Fatigue, joint pain, high blood pressure, nausea, swelling, low potassium, hot flushes, diarrhea, vomiting, cough and headache are the most common side effects.

What is distinctive is the handling and the second product. Abiraterone can harm a developing baby, so women who are or may be pregnant should not handle the uncoated 250 mg tablets, or any abiraterone tablet that is broken, crushed or damaged, without gloves, and men with partners who could become pregnant use effective contraception during treatment and for three weeks after the last dose. Strong CYP3A4 inducers such as rifampin, phenytoin and carbamazepine are avoided, and medicines cleared by CYP2D6 with a narrow margin, such as thioridazine, are avoided or reduced. Yonsa, a separate abiraterone product of 125 mg tablets taken with methylprednisolone and with or without food, carries a label statement that it may not be substitutable for other abiraterone products. Abiraterone is not a controlled substance.

Taking Abiraterone

How to take it

Take the full dose once a day on an empty stomach, with water, at least one hour before or two hours after food, and swallow the tablets whole. Take your prednisone as prescribed, and do not stop either medicine without talking to the prescriber.

If you miss a dose

If you miss one day, take your usual dose the next day. If you miss more than one day, call the prescriber. Do not take a double dose.

Storage

In the original container at room temperature, away from heat and moisture (not in the bathroom), out of reach of children. Women who are or may be pregnant should not handle the uncoated 250 mg tablets, or any broken or crushed tablet, without gloves.

Interactions to know about

Avoid strong CYP3A4 inducers such as rifampin, phenytoin and carbamazepine; if one cannot be avoided, the prescriber may change how often abiraterone is taken. Avoid CYP2D6 medicines with a narrow margin such as thioridazine, watch for low blood sugar with pioglitazone or repaglinide, and tell the pharmacist about St. John’s wort and every other medicine and supplement.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Abiraterone differs from pharmacy to pharmacy

Abiraterone is an oral cancer medicine that many pharmacies fill rarely, so some order it in for each prescription; quotes depend on which generic maker the pharmacy buys from, whether it stocks the 500 mg or only the 250 mg tablet, and whether it is on a flat-price generic list. The same daily dose is two 500 mg tablets or four 250 mg tablets, so the two strengths are often quoted differently for a month.

A prescription for brand Zytiga without substitution is priced as a brand and costs far more than the generics, and Yonsa, being a different product with no generic, is always priced as a brand. The prednisone taken with it is a separate generic prescription.

Ways to pay less for Abiraterone without insurance

• Ask the prescriber to write abiraterone acetate generically and allow substitution; most prescriptions can be filled with a generic 250 mg or 500 mg tablet.
• Ask the pharmacy to quote both the 500 mg and the 250 mg tablet for your monthly dose and ask the prescriber which strength to write.
• Compare more than one pharmacy, since an oral cancer medicine may be ordered in rather than stocked, and ask about a ninety-day supply once treatment is settled.
• If Zytiga or Yonsa brand is prescribed, ask the maker whether its savings or patient assistance program applies to someone paying cash; many copay cards require commercial insurance.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Abiraterone

1. 1.How should I time my abiraterone around meals, and what if I eat by mistake?
2. 2.Can my prescription be filled with a generic, and is the 500 mg tablet the same as two 250 mg tablets for my dose?
3. 3.Do any of my other medicines, such as a seizure medicine, rifampin or a diabetes pill, interact with abiraterone?
4. 4.What should I do if I miss a day, or if I have to stop my prednisone for any reason?

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