Arimidex (anastrozole) is a drug used to treat breast cancer in post-menopausal women. If you have primary breast cancer you will take Arimidex for five years. If you have been changed from Tamoxifen to Arimidex you will continue to take Arimidex for the remainder of your five years of treatment.
Why have I been prescribed Arimidex?
Arimidex (anastrozole) is a drug used to treat breast cancer in post-menopausal women. It is a type of hormone treatment known as an aromatase inhibitor. If you have primary breast cancer you will take Arimidex for five years. If you have been changed from Tamoxifen to Arimidex you will continue to take Arimidex for the remainder of your five years of treatment
How does it work?
Some breast cancers use the female hormone oestrogen to grow. These are described as hormone sensitive or receptor positive tumours. Post-menopausal women do continue to produce oestrogen. Arimidex works by stopping the production of oestrogen so that the amount of oestrogen circulating in the body is reduced.
When and how do I take it?
Arimidex comes as a tablet that you take once a day. It is best to take it at the same time every day. If you miss a dose you don't need to take an extra dose the next day. The level of the drug in your body will remain high from the previous day. It is important not to stop taking Arimidex without talking to your specialist first.
What’s the dose?
1mg once a day.
Could they interact with other tablets?
Drugs containing oestrogen, such as the contraceptive pill or HRT, should not be taken while you are taking Arimidex because they stop it working effectively. There do not seem to be any other prescribed drugs that interfere with Arimidex and other prescribed medicines are not affected if you are taking Arimidex.
Herbal supplements should be used with caution and only after informing your doctor first.
What are the possible risks or side-effects?
More common side effects:
- Stiffness of the joints that is usually mild. You may have menopausal symptoms such as hot flushes. These also tend to be mild and generally wear off after a while. You can do practical things to help yourself such as wearing cotton clothing and reducing your intake of caffeine and alcohol.
- Another menopausal symptom you may notice is vaginal dryness. Vaginal moisturisers or lubricants such as KY Jelly can be helpful. You can get vaginal moisturisers on prescription from your GP. You can buy KY Jelly in most chemists.
- You may also have symptoms such as nausea, vomiting, loss of appetite or diarrhoea. Tiredness may also be a problem for some women, and you may find you need more rest than usual.
Less common side effects:
- You may have other less common side effects such as headache, weakness, a skin rash or sleepiness.
- You may find that your hair gets thinner while you are taking Arimidex. When you stop taking it your hair will usually be the same as it was before.
- Vaginal bleeding is another less common side effect of Arimidex. This can happen in the next few weeks after starting the treatment. It usually occurs when someone has changed from one hormone treatment to another. If you experience bleeding you need to tell your cancer specialist. Do not stop taking your Arimidex without consulting your specialist.
Rare Side Effects:
- There are very rare side effects that may affect your skin, your appetite, or your mood.
Can I drink alcohol while taking it?
Arimidex may cause dizziness. This effect may be worse if you take it with alcohol.
What if I’m pregnant/breastfeeding?
Arimidex must not be administered during pregnancy or breast feeding.
If you have any more questions please ask your Pharmacist.
Remember to keep all medicines out of reach of children
Please Note: We have made every effort to ensure that the content of this information sheet is correct at time of publish, but remember that information about drugs may change. This sheet does not list all the uses and side-effects associated with this drug. For full details please see the drug information leaflet which comes with your medicine. Your doctor will assess your medical circumstances and draw your attention to any information or side-effects which may be relevant in your particular case.