Exemestane

About Exemestane

Exemestane cuts estrogen production by permanently disabling aromatase, the enzyme that makes estrogen in fat and other tissues once the ovaries have stopped; it is a steroidal, irreversible aromatase inactivator. Its labeled uses are for postmenopausal women: adjuvant treatment of estrogen-receptor-positive early breast cancer after two to three years of tamoxifen, continuing to complete five years of hormone therapy in total, and advanced breast cancer that has progressed on tamoxifen. The dose is one 25 mg tablet a day after a meal.

Hot flushes, tiredness, joint pain, headache, trouble sleeping and sweating are the most common side effects. It reduces bone density over time, so women with or at risk of osteoporosis have a bone density scan when they start and bone loss is monitored, and the label recommends checking vitamin D levels before treatment begins. It has no boxed warning; the only contraindication is allergy to it.

Systemic estrogen-containing medicines, such as hormone therapy, work against it. It can harm a developing baby, so anyone who could become pregnant uses effective contraception during treatment and for one month after, and does not breastfeed in that time. The label limits it to women past menopause; MedlinePlus notes it is sometimes prescribed for certain breast cancers before menopause.

Taking Exemestane

How to take it

One tablet once a day after a meal, at about the same time each day, continuing until your prescriber says to stop. People also taking a strong enzyme inducer such as rifampin or phenytoin need a higher dose, set by the prescriber.

If you miss a dose

Take it as soon as you remember, unless it is nearly time for your next dose; in that case skip the missed dose and carry on as usual. Never take two doses at once to make up.

Storage

At room temperature in the original container, tightly closed, away from excess heat and moisture (so not in a bathroom), and out of reach of children.

Interactions to know about

Estrogen-containing medicines such as hormone therapy work against it. Rifampin, phenytoin, carbamazepine, phenobarbital and St. John’s wort lower its levels. Bone density can fall during treatment, so ask about scans and vitamin D testing. Call your prescriber straight away about chest pain or shortness of breath.

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 Exemestane differs from pharmacy to pharmacy

Exemestane has several generic manufacturers, so a pharmacy that buys generics well can price it at a small fraction of the brand, while one dispensing Aromasin, or pricing the generic off the brand’s list price, will quote far more for the same tablet. Because it is taken daily for years, the dispensing fee repeats with every fill.

Not every pharmacy keeps it on the shelf, and one that orders it per prescription may quote more. Cancer centers sometimes send oral cancer prescriptions to their own or a specialty pharmacy, but exemestane needs no refrigeration or special handling, so a retail pharmacy can fill it.

Ways to pay less for Exemestane without insurance

• Ask for generic exemestane, and check that the prescription allows substitution rather than naming Aromasin only.
• Ask whether exemestane is on the pharmacy’s flat-price generic list.
• Ask the prescriber for a ninety-day supply, since treatment runs for years.
• 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 Exemestane

1. 1.Should I take it after breakfast or another meal?
2. 2.Do I need a bone density scan and a vitamin D test before I start?
3. 3.Do any of my medicines or supplements, such as hormone therapy or St. John’s wort, interact with it?
4. 4.What can I do about joint aches and hot flushes?
5. 5.Is a different-looking refill another maker’s generic?

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