Letrozole

About Letrozole

In postmenopausal women, estrogen comes mainly from aromatase, an enzyme that converts adrenal androgens into estrogens, and the growth of some breast cancers depends on estrogen. Letrozole blocks aromatase and so lowers estrogen. The label approves it for postmenopausal women for adjuvant treatment of hormone receptor positive early breast cancer; extended adjuvant treatment of early breast cancer after five years of adjuvant tamoxifen; first-line treatment of hormone receptor positive or unknown, locally advanced or metastatic breast cancer; and advanced breast cancer that has progressed after antiestrogen therapy. The dose is one 2.5 mg tablet once a day, with or without food. In the adjuvant trials the median duration was five years, extended adjuvant treatment was planned for five years, and in advanced disease it continues until the cancer progresses. No dose change is needed for mild to moderate liver impairment or for kidney impairment with a creatinine clearance of at least 10 mL per minute, but people with cirrhosis and severe liver impairment take 2.5 mg every other day. Safety and effectiveness in children have not been established.

There is no boxed warning. Letrozole can decrease bone mineral density, so bone density monitoring may be considered, and it can raise cholesterol, which may be monitored; MedlinePlus advises telling the doctor about high cholesterol, osteoporosis or liver disease before starting. Fatigue, dizziness and sleepiness can occur, so care is needed when driving or using machinery. It must not be taken in pregnancy or by anyone allergic to it or its ingredients. In trials, hot flashes, joint pain, flushing, weakness, swelling, headache, dizziness, raised cholesterol, increased sweating and bone pain were among the most common side effects. MedlinePlus lists muscle, joint or bone pain, tiredness, night sweats and trouble sleeping among the side effects to report if they are severe or do not go away, and chest pain, trouble breathing or sudden weakness or numbness as reasons to call a doctor right away.

Based on postmarketing reports, animal studies and how it works, letrozole can cause fetal harm, so a woman who could become pregnant has a pregnancy test before starting and uses effective contraception during treatment and for at least 3 weeks after the last dose; breastfeeding is avoided for the same period. Animal studies suggest it may impair fertility in women and men. Taken with tamoxifen, letrozole levels fall, although the label says its effect is not impaired when it is started right after tamoxifen. Using letrozole to bring on ovulation is not an FDA-approved use, since the label covers breast cancer only, and the prescriber decides. Kisqali Femara Co-Pack packages letrozole tablets with ribociclib, a different cancer medicine, as a separate product.

Taking Letrozole

How to take it

One tablet once a day, with or without food, at about the same time each day, for as long as the prescriber directs, which may be several years. MedlinePlus says to keep taking it even if you feel well and not to stop without talking to your doctor.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose. Do not take a double dose.

Storage

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

Interactions to know about

Tamoxifen taken at the same time lowers letrozole levels. In studies, cimetidine and warfarin had no clinically significant interaction with it. It can cause dizziness and sleepiness, so take care driving until you know how it affects you.

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 Letrozole differs from pharmacy to pharmacy

Generic letrozole comes in a single strength from several makers and is taken once a day, so quotes for the same quantity differ by each pharmacy’s fee and markup and by whether letrozole is on its flat-price generic list. A prescription that names Femara and blocks substitution must be filled with Femara.

Treatment often lasts years, so whether each fill is for 30 or 90 tablets changes how many dispensing fees are paid over the course of treatment.

Ways to pay less for Letrozole without insurance

• Ask for generic letrozole, and check that the prescription does not block substitution.
• Ask whether letrozole is on the pharmacy’s flat-price generic list, and compare more than one pharmacy.
• Once you are settled on it, ask the prescriber for a ninety-day supply.
• 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 Letrozole

1. 1.Should I have a bone density test, and do I need calcium or vitamin D?
2. 2.Is it safe with tamoxifen or my other medicines?
3. 3.What can I do about joint pain, hot flashes or tiredness?
4. 4.If I could become pregnant, what contraception do I need, and for how long after my last dose?

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