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Letrozole ( Femara®)


Brand name: Femara®  


Generic name: Letrozole   

Therapeutic Class: aromatase inhibitor  

Manufacturer / Distributor: Novartis 

Availability:  Letrozole is available by prescription only  

Dosage form: Letrozole comes as a pill to be taken by mouth 

Indication:  Letrozole is used to treat hormone-dependent breast cancer in postmenopausal women. Letrozole is also used in the treatment of advanced breast cancer in post-menopausal women who were treated unsuccessfully with anti-estrogen therapy. The medication can be taken with no problem right after a surgical therapy,  radiation therapy and/or chemotherapy.  

Letrozole can also be prescribed for other medical conditions not mentioned in this article; talk to your doctor or pharmacist for more information.  

Dosage:  to determine an effective dosage to fight the cancer, your doctor will consider your health, other chemotherapy drugs you are taking, the severity of the tumor and your body mass index (weight / size). Basing on these criteria, your physician will give effective doses of Letrozole capable of combating the cancer.  It is important to adhere to dosage recommended by your doctor; do not change or stop taking the medication if you experience side effects.  

Usually, Letrozole is recommended at a dose of 2.5 mg per day. You can take the drug with or without food, but taking Letrozole after a meal reduces the risk of nausea or vomiting. It is important to take the medication around the same time every day. Depending on your condition, your doctor may recommend you taking Letrozole for years. Even if you feel better, it is necessary that you continue taking the drug. If for valid reasons you cannot continue the therapy, talk to your doctor before taking any decision. 

Storage:  store Letrozole at room temperature (15-25 ° C), away from heat above 40 ° C, light and moisture. Keep the medication out of the reach of children.  Letrozole and all other medications should not be used beyond the expiration date printed on the container.  

Overdose:  as with any drug, Letrozole overdose may be dangerous, mainly if taken for long term. An overdose of Letrozole can damage the bone marrow, and lead to a life threatening decrease in white blood cells and/or in platelets. If you take an overdose, contact your doctor or the poison control center nearest you to reduce or prevent complications.   

Missing dose: always take Letrozole as prescribed.   In case you forget to take a dose, take the missed one as soon as you remember it. However, if it is almost time for your next dose,  do not double the next dose to recover the missing, it can be dangerous. Contact your doctor or wait to go back to your regular schedule. This applies not only to Letrozole but also any other drug. 

Contraindication:  Letrozole is contraindicated in the following conditions: 

  • allergy to Letrozole or any of its ingredients  
  • pre menopause women   
  • pregnant women or women who may become pregnant 
  • Women who are breastfeeding.  

Mechanism of action (MOA):  Letrozole is classed as an aromatase inhibitor, a group of chemotherapy drugs commonly used in the treatment of cancer. It reduces the production of estrogens by blocking aromatase, an enzyme involved in their biosynthesis. The cells of breast cancer are hormone-dependent; they need estrogens to multiply. The reduction of estrogen production can thus limit the proliferation of cancer cells and prevents the tumor from growing or developing.   

Interactions:  before starting a treatment with Letrozole, tell your doctor about all medications you are taking, whether prescription or non prescription. Talk to your doctor before taking vitamins, nutritional supplements or any herbal remedy. Certain medications such as hormone replacement therapy and hormonal contraceptives (birth control pills, patches, rings, and injections), tamoxifen (Nolvadex), and raloxifene (Evista) can  affect the therapeutic property of Letrozole, or increase the risk of developing side effects; contact your doctor before using them. 

Side effects:  Letrozole cause adverse effects in most patients; common Letrozole side effects include:  

  • nausea and vomiting  
  • anxiety  
  • loss of hair  
  • cough   
  • diarrhea  
  • drowsiness   
  • muscle pain  
  • rash or itching  
  • pain or upset stomach  
  • unusual tiredness  
  • fatigue  
  • weight gain  
  • skin redness, warmth in the face and neck   
  • Sweating (hot flushes).   

If the side effects above persist for weeks, contact your oncologist. In addition, contact your doctor if you experience any of these symptoms:   

  • Persistent constipation 
  • confusion 
  • depression 
  • chest pain 
  • difficulty breathing 
  • Persistent cough.   


1 -  santecheznous.com, Quels sont les effets secondaires possibles de ce médicament ? 

2 - nlm.nih.gov, Side effects : Letrexole