Femara (Letrozole): Uses, Side Effects, Dosage

Letrozole (Brand Name: Femara) belongs to a group of anticancer drugs which is used in the treatment of Breast Cancer.

Originally manufactured by Novartis, Femara was approved in 1997 by the Food and Drug Administration (FDA).


Letrozole (Femara) is quickly absorbed with 100% bioavailability, Slow metabolism, the large volume of Distribution, and Time half (t½) of approximately 40 hours.

Femara Uses

  • It is used in estrogen receptor-positive early breast cancer in postmenopausal women,
  • Used in Early invasive breast cancer in postmenopausal ladies when five years of tamoxifen therapy have failed to work.
  • Advanced breast cancer in postmenopausal women.
  • It is additionally employed in pre-operative treatment in postmenopausal women with localized hormone receptor-positive breast cancer.
  • Fertility physicians have used it since 2001 unauthorized because it has fewer side effects such as Clomid (Clomiphene) and a lower risk of multiple  pregnancies.

Note: Your doctor may have suggested this medication for conditions other than those listed in this medication guide.


It is contraindicated in the following conditions:

  • Premenopausal women,
  • Liver disease (especially cirrhosis),
  • Contraindicated in individuals best-known hypersensitivity to the active substance, or to any of the excipients.
  • Osteoporosis,
  • Osteopenia (low bone mineral density),
  • High cholesterol; or
  • if you also take tamoxifen.
  • The use of Femara might cause decreases in the density of your bones, will increase in bone fractures and osteoporosis.
  • Avoid if you are under 18 years of age


Before Taking Femara,

  • Tell your doctor or pharmacist if you are allergic to femara or any other ingredients in this medication.
  • Tell your GP if you have high cholesterol,liver disease and osteoporosis.
  • Tell your doctor about your current as well as past medical history,Other prescriptions and non prescription drugs,nutritional supplement, vitamins, and herbal remedies you are taking.
  • Tell Your Doctor if you are pregnant or planning to become pregnant before starting Femara.
  • Don’t take Femara if you are still having periods as this drug is only used in women who are no longer having periods.
  • Always check the expiry date and Don’t take it after Expiry date printed on the packing.

Femara Mechanism Of Action

Letrozole is a Selective nonsteroidal inhibitor of the aromatase enzyme system; it inhibits the conversion of androgens to estrogens.

In adult nontumor- and tumor-bearing female, letrozole is as effective as ovariectomy in reducing uterine weight, elevating blood serum luteinizing hormone, and inflicting the regression of estrogen-dependent tumors. In distinction to ovariectomy, treatment with letrozole doesn’t cause a rise in serum follicle-stimulating hormone.

Letrozole selectively inhibits gonadal steroidogenesis, however, has no important effect on adrenal mineralocorticoid or glucocorticoid synthesis.

Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, leading to a reduction of estrogen synthesis in all tissues.

Treatment of women with letrozole significantly lowers blood serum estrone, estradiol and estrone sulfate and has not been shown to significantly have an effect on adrenal corticosteroid synthesis, aldosterone synthesis, or synthesis of thyroid hormones.

Drug Interactions

If you take other medicines or over-the-counter medicines at the same time, the effects of Femara may change. This may increase the risk of side effects or make your medications not work properly. Tell your doctor about all the medicines, supplements, herbal remedies, and vitamins you use so that your doctor can help prevent or control drug interactions. Femara can interact with the following medications:

  • Don’t Take letrozole if you are already taking tamoxifen.
  • While an interaction study with warfarin showed no clinically important effect of letrozole on warfarin pharmacokinetics.
  • Cimetidine showed no clinically important effect on letrozole pharmacokinetics.
  • Femara may also interact with Estrogens (Conjugated estrogens and ethinyl estradiol).
  • Avoid eating grapefruit and drinking grapefruit juice while taking letrozole because it slow down how quickly the body is able to break down the letrozole, which could cause letrozole levels in the blood to rise dangerously high.
  • Alcohol or marijuana can make you more dizzy.Limit alcohol while taking Femara.
  • Femara may also interact with Citalopram, Thalidomide and Clopidogrel.
  • It may also Interact with Birth Control pills.

Femara Side Effects

Most common Femara Side effects

The Most Common Femara Side Effects Associated With the use of Femara Include:

  • Nausea,
  • Vomiting,
  • Hot flushes,
  • Dyspepsia,
  • Dizziness,
  • Headache,
  • Diarrhea,
  • Constipation,
  • Anorexia,
  • Depression,
  • Hypercholesteremia,
  • Raised sweating,
  • Alopecia,
  • Increased craving,
  • Peripheral oedema,
  • Skin rashes,
  • Bone fracture,
  • Osteoporosis etc.

Less Common Femara Side Effects

Less common Femara Side effects include

  • Tachycardia,
  • High blood pressure,
  • Palpitation,
  • Cough,
  • Dyspnea,
  • Anxiety,
  • Insomnia,
  • Memory impairment,
  • Taste distrurbance,
  • Urticaria,
  • Pruritis,
  • Dry skin,
  • Urinary frequency,
  • Abdominal pain,
  • Thrombophelbitis,
  • Urinary tract infection,
  • Viginal discharge,
  • Vigina bleeding,
  • Pyrexia,
  • Breast pain,
  • Cataract,
  • Blurred vision,
  • Eye irritation,
  • Leucopenia,
  • Carpal tunnel syndrome,
  • Arthritis,
  • Tumor pain, and
  • General oedema.

Rare Femara side effects

Very rare Femara side effect includes:

  • Arterial thrombosis,
  • Cerebrovascular infarction, and
  • Embolism.

Note: This is not a complete list of Femara side effects. Stop using This drug and Consult your doctors if You experience the above effects or other serious side effects.

Femara In Pregnancy & Breast Feeding

  • Letrozole should be avoided in pregnant women because it causes birth defects in a child. Manufacturer recommendation the use of contraceptives until postmenopausal status totally established.
  • While just in case of lactating women it’s unknown if letrozole is present in human milk. There isn’t any information on the effects of letrozole on the breastfeed infant or milk production.

Femara Dosage

  • The standard recommended dose of Letrozole for all type of breast cancer treatment is 2.5 mg per day without regard to meals.
  • Duration of therapy is usually 5 years but some doctors may recommend it for a longer period of time.
  • If you believe that you have taken an overdose, contact an emergency room or poison center.
  • If you miss a dose of letrozole, try to take it as soon as you remember.
  • However, if it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule.
  • Do not take extra doses to make up for lost ones.

Frequently Asked Questions

Q. Is it safe to use Femara Tablet during pregnancy & Breast Feeding?



Q. Is Femara a Chemotherapy?


Chemotherapy refers to a group of cancer drugs that works by attacking cellular machinery, allowing cells to divide, grow, and spread. Most, but not all, chemotherapy drugs are administered intravenously. Chemotherapy is given in cycles (over a given number of weeks), not every day. Hormonal therapies require the presence of specific receptors (binding sites) in the cancer cell for estrogen and / or progesterone for the treatment to work. Most hormonal therapies are drugs taken daily in the form of tablets. Breast cancer that has neither estrogen nor progesterone receptors does not respond to hormone therapy.

Q. Can I stop immediately or can I slow down my consumption?


Some medications should be immediately reduced or stopped due to rebound effects. Consult your doctor for specific recommendations for your body, health and other medicines that you may use.

Q. Is it safe to drive or use heavy machinery when used?


You should not drive if you feel drowsy, dizzy or low blood pressure by taking the Femara Tablets. Pharmacists also recommend patients that they do not drink alcohol with medication as alcohol increases the side effects of drowsiness. Please check these effects on your body when using Femara Tablet. Always consult your doctor for special recommendations on body and health.

Q. Is Femara cause addiction or adaptation?


Most medicines have no abuse.Do not medicate yourself and increase the body’s dependence on medication without the advice of a doctor.

Q. Can you drink while on letrozole (Femara)?


Letrozole and alcohol can both cause headaches and nausea, and these side effects may worsen if you take both drugs at the same time. If possible, try to avoid or restrict alcohol consumption while taking letrozole. Always Consult your Doctor before using Femara with Other drugs.


4 thoughts on “Femara (Letrozole): Uses, Side Effects, Dosage

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