Meds and you

27 September 2013


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


Letrozole is the active ingredient of Femara tablets (Nappi code: 831468-009).

General information

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

In South Africa letrozole 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.

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 letrozole work?

Letrozole 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 90%. By lowering oestrogen levels in the body, letrozole effectively "starves" the breast cancer cells, thereby inhibiting their growth.

Fast facts

Drug schedule: schedule 4

Available as: letrozole is available as tablets

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

Overdose risk: low

Dependence risk: low

Is letrozole available as a generic? no

Is letrozole available on prescription only? yes

User information

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

Special precautions

Consult your doctor before using this drug if:

- you have 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 effect Frequency
Consult your doctor

Common Rare Only if severe In all cases
Headache x
Hot flushes x
Dizziness x
Fatigue x
Nausea x
Dry mouth x
Hair loss
x x
Muscle pain
x x
x x
Breathing difficulties


Drug interactions

Oestrogen Oppose the effect of letrozole

Overdose action

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

Recommended dosage

Adults, oral: 2.5mg once daily

Interesting fact

Although not indicated, it has been used for ovulation induction by fertility doctors; it has fewer side effects than clomiphene citrate (Clomid) for the patient and may lower the risk of multiple gestation.

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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