Anastrozole

About Anastrozole

After menopause most estrogen is made by aromatase, an enzyme that converts adrenal hormones into estrogen; anastrozole blocks it and lowers estradiol, a hormone that stimulates or maintains the growth of many breast cancers. The label covers three uses, all in women after menopause: adjuvant treatment of hormone receptor-positive early breast cancer; first-line treatment of locally advanced or metastatic breast cancer that is hormone receptor-positive or of unknown receptor status; and advanced breast cancer that has progressed on tamoxifen, where estrogen receptor-negative tumors rarely respond. The dose is one 1 mg tablet a day, with or without food, with no change for kidney impairment or mild to moderate liver impairment. In advanced disease it continues until the cancer progresses; for early disease the ideal length of treatment is not known, and the main trial used five years.

There is no boxed warning, and the only contraindication is an allergic reaction to anastrozole or its ingredients; anaphylaxis, swelling of the face and throat, and hives have been reported. In women with existing ischemic heart disease, the main trial found more ischemic cardiovascular events than with tamoxifen, so the label asks prescribers to weigh benefits and risks. It lowers bone mineral density, so bone density may be monitored, and it can raise cholesterol, which may be checked. Hot flashes, weakness, joint pain, back pain, depression, trouble sleeping, headache, nausea, rash, high blood pressure and swelling of the limbs are common; carpal tunnel syndrome, trigger finger, hepatitis and severe skin reactions such as Stevens-Johnson syndrome have also been reported.

It is not combined with tamoxifen, because in the main trial the combination worked no better than tamoxifen alone, and estrogen-containing therapies are not used with it because they may weaken its effect. The label notes it would not be expected to lower estradiol before menopause. It can harm a developing baby, so pregnancy status is checked before starting in anyone who could become pregnant, effective contraception is used during treatment and for at least three weeks after the last dose, and breastfeeding is avoided during treatment and for two weeks after. Trials in boys with breast enlargement at puberty and girls with McCune-Albright syndrome did not show that it works, and it is not approved for children. MedlinePlus notes it is sometimes prescribed to lower the chance of breast cancer in women at high risk, a use the label does not include.

Taking Anastrozole

How to take it

One tablet once a day, with or without food, at about the same time each day. Keep taking it for as long as your prescriber directs, which may be several years or longer.

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 and continue your usual schedule. Do not take a double dose.

Storage

At room temperature in the original container, tightly closed, away from excess heat and moisture (so not in a bathroom), out of reach of children. Use a take-back program rather than flushing it.

Interactions to know about

Tamoxifen is not taken with it, and estrogen products, including hormone therapy, estrogen creams, patches, rings and birth control pills, can make it less effective; mention raloxifene too. Tell the prescriber about heart disease, high cholesterol, osteoporosis or liver disease, and get medical help at once for chest pain, shortness of breath, blisters, a rash or hives, or swelling of the face or throat.

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 Anastrozole differs from pharmacy to pharmacy

Anastrozole is an old generic with several makers and costs pharmacies little, so a quote for the generic is mostly the dispensing fee and markup, and whether it sits on a pharmacy’s flat-price generic list varies. Treatment usually lasts years, so the fee repeats with every fill unless a ninety-day supply spreads it over three months.

A prescription that names Arimidex and blocks substitution is filled with the brand at a brand price.

Ways to pay less for Anastrozole without insurance

• Ask for generic anastrozole, and check that the prescription allows substitution rather than naming Arimidex only.
• Ask whether anastrozole is on the pharmacy’s flat-price generic list, and compare more than one pharmacy.
• Once the treatment plan is settled, ask the prescriber for a ninety-day supply with refills.
• 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 Anastrozole

1. 1.Will my bone density and cholesterol be checked while I take it?
2. 2.Do any of my medicines, such as hormone therapy, an estrogen cream or tamoxifen, interfere with it?
3. 3.What can I do about joint pain, stiffness or hot flashes?
4. 4.Which symptoms, such as chest pain or a blistering rash, mean I should get help right away?

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