Anastrozole (brand name Arimidex) is occasionally used to supplement low testosterone. This drug works by decreasing the amount of estrogen the body makes.
It was originally developed to treat what’s called hormone receptor-positive breast cancer in postmenopausal women. Hormone receptor-positive means that the cancer cells grow in response to the hormone estrogen, which explains why anastrozole can treat these kinds of breast cancers.
Currently, anastrozole is only FDA-approved for use in women. But like clomiphene, some providers prescribe anastrozole off-label to treat low testosterone in men. However, there isn’t enough evidence to recommend it as a standard treatment for low T.
Anastrozole is used to treat early hormone receptor-positive breast cancer. It is also used for first-line treatment of hormone receptor-positive or hormone receptor-unknown advanced or metastatic (cancer that has spread) breast cancer. Anastrozole is also used to treat advanced breast cancer that has grown or spread after tamoxifen treatment. This medicine is used only in women who have already stopped menstruating (postmenopausal).
Many breast cancer tumors grow in response to estrogen. This medicine interferes with the production of estrogen in the body. As a result, the amount of estrogen that the tumor is exposed to is reduced, limiting the growth of the tumor.
This medicine is available only with your doctor’s prescription.
Anastrozole lowers estrogen levels in postmenopausal women, which may slow the growth of certain types of breast tumors that need estrogen to grow in the body.
Anastrozole is used to treat breast cancer in postmenopausal women. It is often given to women whose cancer has progressed even after taking tamoxifen (Nolvadex, Soltamox).
Anastrozole may also be used for purposes not listed in this medication guide.
Anastrozole may decrease blood flow to your heart, especially if you have ever had coronary artery disease (clogged arteries). Seek medical attention if you have new or worsening chest pain, or if you feel short of breath.
Before Taking This Medicine
You should not use anastrozole if you are allergic to it, or if you have not yet completed menopause.
Anastrozole is not approved for use in men or children.
You should not take anastrozole if you also take tamoxifen.
Tell your doctor if you have ever had:
- heart problems;
- coronary artery disease (clogged artery disease);
- high cholesterol; or
- osteoporosis or low bone mineral density.
Hormonal cancer treatment can weaken your bones. You may be more likely to have a broken bone while using anastrozole. Talk with your doctor about ways to keep your bones healthy.
Although it is not likely that a postmenopausal woman would be pregnant, anastrozole may harm an unborn baby. You may need to have a negative pregnancy test before starting this treatment. Use effective birth control if you are not past menopause. Keep using birth control for at least 3 weeks after your last dose of anastrozole. Tell your doctor if you become pregnant.
Do not breastfeed while using anastrozole, and for at least 2 weeks after your last dose.
Usual Adult Dose For Breast Cancer:
Initial dose: 1 mg orally taken once a day
Duration of therapy: Until tumor progression (treatment of advanced breast cancer); unknown (adjuvant treatment of early breast cancer)
-Adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer;
-First-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer;
-Second-line treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy.
How To Cope With The Side Effects Of Anastrozole
Menopause symptoms such as hot flushes, difficulty sleeping, tiredness and low mood usually improve during the first months of taking anastrozole. However, if they are severe or last longer than a few months, talk to your doctor or breast cancer nurse.
What To Do About:
- hot flushes and sweating – try cutting down on spicy food, caffeine, smoking and alcohol. It may help to keep the room cool and use a fan. Try spraying your face with cool water, or sipping a cold drink.
- dry or itchy vagina, bleeding from your vagina – ask your doctor or breast cancer nurse to recommend a vaginal moisturiser for treating irritation or dryness. Vaginal bleeding usually happens in the first few weeks after starting anastrozole. Talk to your doctor if it lasts longer than a few days. Also talk to your doctor if these symptoms first appear more than a few weeks after you start taking anastrozole.
- difficulty sleeping – avoid caffeine (tea, coffee, cola and chocolate) in the afternoon and evening. Keep your bedroom dark and quiet, and try going to bed and getting up at a set time each day. It may also help to stop watching TV, looking at your mobile phone or using other electronic devices (like tablets), at least 1 hour before bedtime.
- feeling very tired – gentle exercise and eating healthily can help make you feel less tired. Try going to bed and getting up at a set time each day. Do not drive, ride a bike or operate machinery if you feel very tired while taking anastrozole. This will usually start to improve as your body gets used to the medicine. Speak to your doctor if it does not get better.
- feeling or being sick, loss of appetite – it might help to take anastrozole after you’ve eaten. Choose foods you normally enjoy but avoid rich or spicy food. Try eating smaller meals but more often. If you’re being sick, have small, frequent sips of water to avoid dehydration. Talk to your doctor if your symptoms do not improve or get worse.
- mild aches in your muscles or bones – ask a pharmacist to recommend a suitable painkiller. If the pain lasts more than a week, ask your doctor for advice. If you have a sudden attack of pain in a joint ask a doctor for advice urgently.
- numb or tingling hands – stop taking the medicine and ask your doctor for advice
- changes to your skin, including a mild rash – it may help to take an antihistamine. You can buy these at a pharmacy without a prescription. Check with a pharmacist to see what’s suitable for you.
- hair loss or thinning hair – some people find that their hair gets thinner when they start taking anastrozole. This is usually mild. Ask your breast cancer nurse for advice if this is bothering you.
- low mood or depression – it is difficult to know whether this is due to the medicine or a response to menopausal symptoms or being diagnosed with cancer. Speak to your doctor or specialist nurse. They may recommend therapies, like cognitive therapy and mindfulness, or antidepressant medicines.
Pregnancy And Breastfeeding
Anastrozole is not recommended when pregnant or breastfeeding, because it interferes with hormone levels in you and your baby. And there is not enough information available to say if it’s safe.
Talk to your doctor straight away if there is any chance that you could be pregnant.
The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.