Arimidex
® (
anastrozole) is a prescription medication used to treat
breast cancer in postmenopausal women. Specifically, the drug has been licensed to treat postmenopausal women who have:
- Early breast cancer that is hormone receptor-positive
- Advanced or metastatic breast cancer that is either hormone receptor-positive or the hormone receptor status is not known
- Advanced breast cancer that has not responded to tamoxifen (Nolvadex®, Soltamox®).
Arimidex is made by AstraZeneca Pharmaceuticals.
Arimidex is part of a group of medications called aromatase inhibitors. Aromatase is an enzyme found in various places in the body. These enzymes help produce estrogens (in particular, a certain estrogen called estradiol). In postmenopausal women, most of the estrogen in the body is made by aromatase. By blocking these enzymes, Arimidex helps to decrease the amount of estrogen in the body.
Many breast cancers are sensitive to the estrogen hormone, meaning that the tumor grows with the help of estrogen. When a tumor is sensitive to estrogen, it has receptors on the outer surface of its cells. Estrogen fits into these receptors like a key opening a lock. When this connection is made, the cancer grows.
Breast cancers that have estrogen (and/or progesterone) receptors are known as hormone receptor-positive tumors.
Several studies have looked at the effects of Arimidex in women with
breast cancer.
One large study looked at using the drug for the adjuvant treatment of early breast cancer.
Adjuvant therapy for breast cancer is treatment that follows
breast cancer surgery (with or without radiation). It is given to help prevent the cancer from returning. These studies compared Arimidex with
tamoxifen (
Nolvadex, Soltamox) in postmenopausal women with hormone receptor-positive cancer.
After five years, up to 17 percent more women taking Arimidex were cancer-free, compared to those taking tamoxifen. In this particular study, women taking Arimidex were also less likely to stop the medicine because of side effects when compared to women taking tamoxifen. This study also showed that taking both breast cancer medications together did not offer any advantage.
Two other large studies compared Arimidex to tamoxifen in postmenopausal women with advanced or metastatic breast cancer. These women had tumors that were either hormone receptor-positive or the receptor status was not known. In these studies, Arimidex was at least as effective as tamoxifen in how the cancer responded to the medication (either by shrinking the tumor or stopping its growth) and time to progression.
"Time to progression" is a medical term that means from the time that the cancer is treated until the disease starts to get worse, such as when the cancer spreads (metastasizes) or the tumor increases in size. For these studies, time to progression was, on average, up to 11.1 months for Arimidex and, on average, up to 8.3 months for tamoxifen.
There were also two studies that showed Arimidex may be effective for treating advanced breast cancer that has not responded to tamoxifen in postmenopausal women. These studies included women who had breast cancer that was hormone receptor-positive. Women with hormone receptor-negative breast cancer were included only if they had originally responded to treatment with tamoxifen.
General considerations for when and how to take Arimidex include the following:
- The medication comes in tablet form and is taken by mouth once a day.
- It can be taken with or without food. If Arimidex bothers your stomach, try taking it with food.
- Arimidex should be taken at the same time each day to maintain an even level in your blood.
- For the medication to work properly, it must be taken as prescribed. Arimidex will not work if you stop taking it.
The dose of Arimidex your healthcare provider recommends will vary, depending on a number of factors, including:
As is always the case, do not adjust your dose unless your healthcare provider specifically instructs you to do so.
As with any medicine, side effects are possible with Arimidex. However, not everyone who takes the drug will experience side effects. In fact, most people tolerate it quite well. If side effects do occur, in most cases, they are minor and either require no treatment or can easily be treated by you or your healthcare provider. Serious side effects are less common.
Common side effects include but are not limited to:
(Click Arimidex Side Effects to learn more, including potentially serious side effects you should report immediately to your healthcare provider.)
The following eMedTV articles describe specific side effects of the drug:
What Should I Tell My Healthcare Provider Before Taking Arimidex?
You should talk with your healthcare provider prior to taking this drug if you have:
Also, let your healthcare provider know if you are:
Make sure to tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.
What If I Take an Overdose?
People who take too much Arimidex may have symptoms that include:
- Stomach pain
- Blood in the stool
- Nausea and vomiting.
If you happen to take too much, seek immediate medical attention.
How Should Arimidex Be Stored?
Arimidex should be stored at room temperature, away from moisture and heat. Keep this and all medications out of the reach of children.
What Should I Do If I Miss a Dose?
If you do not take your Arimidex as scheduled, take your missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose.
Arimidex is available in one strength -- Arimidex 1 mg tablets.
Is There a Generic Version of Arimidex?
Currently, there are no generic versions of Arimidex licensed for sale
(see Generic Arimidex).
