Meds and you

27 September 2013


Anastrozole is an antineoplastic. Antineoplastics are drugs that prevent the development or growth of cancer cells.


Anastrozole is the active ingredient of Arimidex tablets (Nappi code: 824224-019).

General information

Anastrozole is an antineoplastic. Antineoplastics are drugs that prevent the development or growth of cancer cells.

In South Africa anastrozole is registered for the treatment of early and advanced breast cancer in postmenopausal woman. It has not proved effective in cancers that are not oestrogen-sensitive.

For this medication to be effective, it has to be taken regularly, even if you do not notice an immediate effect.

Vaginal bleeding may occur in the first few weeks after changing over from other hormonal therapy. If the bleeding persists, it should be evaluated.

Be careful if you drive or do anything that requires you to be alert. Avoid any other dangerous activity until you know how this medication affects you.

How does anastrozole work?

Anastrozole inhibits an enzyme which is partially responsible for the production of natural oestrogens in the body. As a result, oestrogen production is reduced by as much as 80%. By lowering oestrogen levels in the body, anastrozole effectively "starves" the breast cancer cells, thereby inhibiting their growth.

Fast facts

Drug schedule: schedule 4

Available as: anastrozole is available as tablets.

What does it do? Anastrozole slows the progression of breast cancers, most of which are stimulated by oestrogens.

Overdose risk: low

Dependence risk: low

Is anastrozole available as a generic? no

Is anastrozole available on prescription only? yes

User information

Onset of effect: within 24 hours

Duration of action: up to 6 days

Stopping this medicine: do not stop taking this drug without consulting your doctor.

Special precautions

Consult your doctor before using this drug if:

  • youhave osteoporosis
  • you have any doubt as to whether or not your menopause has taken place
  • you have kidney or liver disease

Pregnancy: avoid. Potential risk to the foetus has been reported. Consult your doctor before use, or if you are planning to fall pregnant.

Breastfeeding: avoid. This medication is passed through breastmilk and may affect your baby adversely. Consult your doctor before use.

Porphyria: avoid. It is unknown how this medication may affect your condition. Consult your doctor before use.

Infants and children: this medication is not intended for use in children.

The elderly: no special precautions need to be taken.

Driving and hazardous work: caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.

Possible side effects



Side effects Frequency   Consult your doctor  
  Common Rare Only if severe In all cases
headache x   x  
hot flushes x   x  
dizzieness x   x  
fatigue x   x  
nausea x   x  
dry mouth x   x  
hair loss   x x  
muscle pain   x x  



Drug interactions



oestrogen opposes the effect of anastrozole
tamoxifen opposes the effect of anastrozole


Overdose action

A small overdose is no cause for concern. In case of intentional large overdose, seek emergency medical attention.

Recommended dosage

Adults, oral: 1 mg once daily

Interesting fact

Although not indicated, this drug is frequently used in the treatment of children with growth disorder to stop or slow the onset of puberty.


This material is not intended to substitute medical advice, but is for informational purposes only.

               Please consult a physician for specific treatment and recommendations.




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