Femara: Uses, Dosage, Side effects and Interactions

Research Based
Medically reviewed by - Dr Rabia Akram, MD Written by - Dr. Shilpa R


What is Femara?

Femara comes with a chemical name called letrozole. Femara is used in the treatment and intervention of hormone receptor-positive breast carcinoma in females who have reached menopause.

Femara is an oral medication that can be used as an effective treatment for women experiencing ovulation difficulties or unexplained infertility.

This medication belongs to the class of drugs named as inhibitors of aromatase. Femara is purposefully indicated for the treatment of postmenopausal women with cancer. This medication is approved for the management of hormone receptor-positive (HR+) breast cancer only as it is ineffective against hormone receptor-negative breast cancer.

Femara comes with a chemical name called letrozole. Femara is used in the treatment and intervention of hormone receptor-positive breast carcinoma in females who have reached menopause.

How does Femara work?

  • Letrozole decreases the levels of the estrogen hormone. Estrogen encourages the growth of few types of breast cancers classified as hormone sensitive or hormone receptor positive cancers.
  • Letrozole/Femara has the potential to inhibit the growth of these cancer types.
  • After menopause, women do not have estrogen production from their ovaries. However, a minimal quantity is still synthesized via the utilization of the enzyme aromatase. This process converts androgens into estrogen. The primary sites of this change are adipose tissue, skin and skeletal muscles.
  • Letrozole is grouped under an aromatase inhibitor medication. The inhibition of aromatase halts the conversion of androgens to estrogen.


Uses of Femara

Femara aka Letrozole, an aromatase inhibitor approved for:

  • Treatment of Breast cancer
  • Treatment of Ovulation in women suffering from PCOS (Polycystic ovarian syndrome)
  • Treatment of infertility

Treatment of breast cancer (all stages)

For individuals diagnosed with early-stage, hormone receptor-positive breast cancer, there are 2 ways Femara can be used:

  • Femara is the initial hormonal therapy medication prescribed following breast cancer surgery, generally taken for a duration of five years.1Uses| Researched based study from Later, if tamoxifen has been administered for a period of five years, Femara may be prescribed as a secondary hormonal therapy medication.
  • Femara is normally prescribed for a duration of five years, resulting in a total hormonal therapy period of 10 years.

Treatment of Ovulation

  • Femara (Letrozole) medication inhibits the enzyme aromatase and reduces levels of estrogen. This leads to rise in the synthesis of follicle stimulating hormone (FSH) by the pituitary gland and brain.1Uses| Researched based study from
  • Anovulation and Polycystic ovary syndrome (PCOS) are health conditions in females that can cause the growth and development of a mature follicle in the ovary. It causes ovulation of an egg due to an increase in FSH levels in women. This is referred to as “ovulation induction”.

Treatment of Infertility

  • Femara treatment in women with regular ovulation can induce the growth of multiple follicles and cause the release of multiple eggs. Releasing multiple eggs can enhance the chances of pregnancy compared to the release of a single egg during a natural menstrual cycle.1Uses| Researched based study from

Side effects

Side effects of Femara

The side effects of Femara include:

  • Elevated cholesterol levels
  • Carpal tunnel syndrome
  • Menopausal symptoms
  • Excessive sweating
  • Joint pain
  • Fatigue
  • Tiredness
  • Osteoporosis (thinning of the bone)
  • High BP
  • Low mood and depression
  • Headache
  • Dizziness
  • Nausea and vomiting
  • Changes in the hair
  • Changes in the skin
  • Vaginal bleeding
  • Tachycardia
  • Edema

Elevated cholesterol levels

  • Elevated blood cholesterol levels can occur. A slight rise necessitates regular blood tests for monitoring purposes.

Carpal tunnel syndrome (CTS)

  • Carpal tunnel syndrome (CTS) is specified by compression of the median nerve. It crosses across the carpal tunnel seen in the wrist. It results in tingling, discomfort and loss of sensation in the arm, fingers and hand. The symptoms can be reduced by using wrist splint.

Menopausal symptoms

  • Menopausal symptoms can include sweating, hot flashes, sleep disturbances, vaginal irritation such as itching and drying, and reduced libido. Symptoms often resolve with the passage of time.

Excessive sweating

  • Excessive sweating in the axilla, soles and palms may be observed. Inform your healthcare provider about the situation as they may possess the ability to provide assistance.

Joint pain

  • You may experience joint pain. Consult your healthcare provider regarding suitable pain medication options for this condition.2Side effects| Researched based study from

Fatigue, or tiredness

  • Fatigue and low energy levels may be experienced. Exercise is one method that can assist in reducing fatigue and effectively managing it. Research suggests that engaging in low-intensity physical activity can potentially enhance energy levels. Maintaining a balance between physical activity and rest is important.


  • Letrozole decreases endogenous estrogen levels. Osteoporosis or thinning of bone can be caused by long-term estrogen deficiency.2Side effects| Researched based study from
  • A bone scan may be done to assess bone strength and density prior to or shortly after commencing letrozole treatment. To promote bone health, it is advisable to enhance calcium and vitamin D consumption. The majority of individuals achieve this by consuming a dietary supplement.

Low mood and depression

  • You may experience feelings of low mood or depression. Finding out the cause of these symptoms is challenging, as they may be due to to medication, menopausal symptoms, or the emotional burden of a cancer diagnosis.

High blood pressure

  • Letrozole has the potential to induce hypertension in certain individuals. Your general practitioner (GP) can provide monitoring and treatment if required.2Side effects| Researched based study from


  • Letrozole may induce headaches as a potential side effect. Paracetamol can provide mild relief for headaches.


  • Letrozole can induce dizziness. It is suggested to refrain from driving if experiencing dizziness. If you have persistent dizziness, it is advisable to consult with your general practitioner (GP).

Nausea and vomiting

  • Letrozole may induce nausea or vomiting as side effects. Symptoms usually go off on their own.

Changes in hair or facial hair

  • Hair loss or thinning may occur during the administration of letrozole. A minority of women experience a rise in facial hair.

Changes in the skin

  • Skin changes like change in appearance, texture, or condition of the skin. Letrozole usage may result in the occurrence of a skin rash. This side effect resolves upon completion of the prescribed treatment.

Vaginal bleeding

  • Vaginal bleeding occurs during the initial weeks of letrozole therapy. Vaginal dryness may also lead to bleeding. If the bleeding persists beyond a few days, it is advisable to inform your healthcare provider.


  • Letrozole administration may induce heart palpitations, a sensation of rapid heartbeats, particularly among older individuals. Chest pain may also be experienced by certain individuals. If you experience any of these symptoms, please consult your general practitioner or treatment team.


  • Swelling can occur in the arms, hands, feet, and ankles. If you observe any swelling, including this one, please inform your general practitioner.2Side effects| Researched based study from

Studies indicate that a significant proportion of women who use Femara or other hormonal therapy medications discontinue their usage prematurely, due to the presence of uncomfortable side effects. It is important to note that sticking to the recommended duration of hormonal therapy can decrease the chances of cancer recurrence by 50% and lower the risk of death from breast cancer by approximately 30%.


Femara Dosage instructions

Daily Dose

  • Femara 2.5mg Tablet may be managed either with or without food, although best results are seen when taken regularly at a fixed daily schedule. The medication Femara is sold in the form of a 2.5 mg pill with an enteric coating.
  • Femara is an oral medication available in the form of 2.5 mg tablets. The recommended dosage for breast cancer treatment is a single oral tablet. The recommended dosage for adjuvant treatment of breast cancer is also one tablet daily.1Dosage| Researched based study from

In case of Missed Dose

  • In the circumstance, if a missed dose of Femara, it is advisable to promptly take the missed dose unless it coincides with the scheduled time for the next dose. In such situations, it is advisable to omit the missed out dose and proceed with one’s regular daily routine.
  • Do not pump up the dosage to compensate for a missed dose.

In case of Overdose

  • In the circumstance of an excessive dosage, it is advisable to promptly seek emergency medical attention or consult a healthcare professional. Common symptoms of Femara include nausea, vomiting, headache, and hot flashes.


Femara storage

  • The product Femara is contained in HDPE bottles equipped with a secure screw cap. They are 2.5 mg dosed tablets. The femara tablets are packaged and sold in bottles having 30 tablets each.
  • The recommended storage temperature is 25°C (77°F), with allowable temperature excursions ranging from 15 to 30°C (59 to 86°F).


Precautions and warnings

Regular monitoring of BMD

  • Femara usage may lead to reductions in bone mineral density (BMD). Monitoring BMD should be considered.1Precautions| Researched based study from

Fertility issues

  • This treatment is recommended exclusively for individuals who have completed the menopausal phase. Due to its mechanism of action, the chances of pregnancy are minimal. Your doctor will discuss the optimal contraceptive method with you.

Embryo-fetal toxicity

  • Pregnancy remains a possibility during the initial stage of menopause. This medication has the potential to cause harm to a developing fetus. Avoiding pregnancy during and shortly after treatment is important.
  • Animal studies have demonstrated that doses significantly lower than the recommended human daily maximum dose on a mg/m2 basis can cause embryotoxicity, fetotoxicity, and teratogenicity.
  • The adverse effects included heightened toxicity in embryos and fetuses, loss of pregnancies before and after implantation, decreased number of live fetuses, reduced fertility as sexual inactivity in females, atrophy of the reproductive tract in males and females, and no success in mating and achieving pregnancy.

Pediatric Application

  • The safety and efficacy of this treatment in pediatrics patients has not been established.

Hepatic impairment

  • Patients with severe hepatic impairment like cirrhosis who received a 2.5 mg dose of Femara showed approximately two fold higher levels of Femara exposure compared to healthy volunteers who had normal liver function.
  • Hence, it is advisable to reduce the dosage for this specific group of patients. The impact of hepatic impairment on the exposure of Femara in cancer patients with raised bilirubin levels still remains unknown.


  • Serum cholesterol monitoring should be considered. In the adjuvant trial, the occurrence of hypercholesterolemia was observed in 52.3% of patients treated with letrozole and 28.6% of patients treated with tamoxifen.1Precautions| Researched based study from


  • Avoid breastfeeding while undergoing this treatment due to the potential transfer of the drug into breast milk.

Treatment for additional conditions

  • It is important to inform healthcare professionals about undergoing this treatment. For instance, if treatment is required for any other medical conditions, including dental issues.

Fatigue and dizziness

  • You can feel sleepy or lightheaded after taking this medication, and infrequently your eyesight might get blurry. The intake of either marijuana or alcohol (cannabis) may result in increased dizziness or fatigue.
  • Avoid operating vehicles, machinery, or engaging in activities that require concentration or sharp vision until you are able to do so safely. Do not consume alcoholic beverages. Consult your healthcare provider if you are using marijuana (cannabis).




  • Letrozole has the potential to cause enough harm to the fetus during pregnancy.


  • Known Hypersensitivity or reaction to the active substance or any of the excipients is a recognized contraindication.


Drug Interactions

Inform your healthcare team of any medications you are currently using any medication. This includes herbal supplements, vitamins and non-prescription remedies. It is important to inform your doctor about any prevalent medical conditions or allergies you may have.

Some of major drug interactions of Femora are:

Estrogen derivatives

  • It is advisable to avoid the use of estrogen derivatives, such as estradiol, in conjunction with letrozole or anastrozole, as they have the potential to diminish the effectiveness of these medications and give reduced protection against breast cancer.3Interactions| Researched based study from


  • The simultaneous use of Femara and tamoxifen at a daily dose of 20 mg led to an average decrease of 38% in letrozole plasma concentrations. Clinical experience in second-line breast cancer trials suggests that the therapeutic efficacy of Femara treatment remains unaffected when administered immediately after tamoxifen.3Interactions| Researched based study from


  • The pharmacokinetic interaction study involving cimetidine did not result in any clinically significant impact on the pharmacokinetics of lethal .


  • The interaction study between letrozole and warfarin did not demonstrate any clinically significant impact of letrozole on the pharmacokinetics of warfarin.

Additional anticancer agents

  • Currently, there is a lack of clinical evidence regarding the combined use of Femara with other anticancer agents.


  • The co-administration of letrozole has been found to reduce the metabolism of Acetaminophen.


  • The co-administration of Letrozole and Benzocaine may elevate the risk or severity of methemoglobinemia.


  • The combination of Letrozole and Acipimox may increase the risk and severity of myopathy, rhabdomyolysis, and myoglobinuria.

Food & Supplements

  • Cancer drugs have the potential to interact with medications, herbal products, as well as certain food and beverages. Grapefruit or grapefruit juice can increase the side effects of specific medications.3Interactions| Researched based study from

Vs Clomid

Femara Vs Clomid

About Clomid

  • Clomid is a generic brand. Clomiphene Citrate is a fertility medication given orally. It is given to induce ovulation in women with anovulation.
  • Clomid functions by inhibiting estrogen receptors, thereby increasing the secretion of hormones necessary for the stimulation of ovarian follicle development. FSH and LH hormones stimulate the development of egg follicles in the ovaries of women.4Vs clomid| Researched based study from

Advantages of Femara over Clomid

  • The ovulation rate of women using Femara is higher compared to those using Clomid.
  • The live birth rates achieved with Femara are higher compared to those achieved with Clomid.
  • The utilization of Femara has been found to increase pregnancy success rates among overweight women.
  • The success rates of Femara and Clomid were similar across the various Body Mass Index (BMI) groups that were examined.
  • Research has indicated that the chances of getting pregnant using Femara is similar to the success rates observed with Clomid.4Vs Clomid| Researched based study from
  • The concurrent administration of Femara and Intrauterine Insemination (IUI) significantly increases the probability of achieving pregnancy in women.
  • The administration of Femara is associated with a monthly increase of 15% in a woman conceiving. Femara has been effective in inducing ovulation in women with anovulation.


The Outlook

Femara aka Letrozole is a non steroidal drug that inhibits aromatase. It is mainly utilized for the use of breast cancer treatment in women who have attained menopause. If adverse effects arise from the use of Femara or any other hormonal therapy medication, it is advisable to promptly consult with a healthcare professional.

Disclaimer: The user acknowledges that this article's information is being offered for informational purposes only. Every attempt has been made to guarantee that the article is informational and correct. If they have any doubts or questions about their health, we firmly advise our readers to visit a doctor or other healthcare professional.

Related Articles

subscribe drcure
subscribe drcure
Thanks for subscribing
Look out for our email. Follow our social pages