Femara is a brand-name prescription drug that’s approved to treat breast cancer in women who’ve gone through menopause.

Femara is approved to treat breast cancer that’s hormone receptor-positive (HR+). This type of breast cancer is stimulated to grow by hormones, including estrogen. Femara can also be used to treat certain types of breast cancer whose hormone receptor status isn’t known.

Femara is prescribed for women with certain forms of either early or advanced breast cancer. With early breast cancer, the cancer hasn’t spread out of either your breast or the lymph nodes in your armpit. But with advanced breast cancer, the cancer has spread to nearby areas or lymph nodes (called locally advanced breast cancer), or it has spread to other parts of the body (called metastatic breast cancer).

Femara is used in the following ways for early HR+ breast cancer:

  • Adjuvant treatment. For this use, Femara is given to help lower the risk of the breast cancer coming back after it’s been treated with surgery.
  • Extended adjuvant treatment. For this use, Femara is given to help lower the risk of the breast cancer coming back after it’s been treated with both surgery and 5 years of tamoxifen (another cancer drug).

Femara is used in the following ways for advanced breast cancer that’s either HR+ or whose hormone receptor status isn’t known:

  • First-line treatment. With first-line treatment, Femara is the first drug given to treat the advanced breast cancer.
  • Second-line treatment. With second-line treatment, Femara is given to treat the advanced breast cancer after certain past therapy hasn’t worked. For this use, Femara can treat advanced breast cancer that has come back or spread after other treatments.

Femara contains the drug letrozole. It’s a hormone therapy for breast cancer. These types of therapies stop estrogen from encouraging breast cancer cells to grow. More specifically, Femara is a type of hormone therapy called an aromatase inhibitor. It works by lowering the amount of estrogen your body makes.

Femara comes as tablets that are taken by mouth. It’s available in one strength: 2.5 mg.

Effectiveness for breast cancer

In several clinical studies, Femara was more effective than the cancer drug tamoxifen in treating breast cancer. In fact, aromatase inhibitors like Femara are recommended in current guidelines for people with HR+ breast cancer.

In studies of women with early breast cancer, Femara was more effective than tamoxifen was in preventing their breast cancer from coming back or spreading after surgery. In one study, women who took Femara for 5 years after surgery were 13% less likely to have their breast cancer come back or spread than were women who took tamoxifen for 5 years after surgery.

Another study showed that in women with early breast cancer, taking Femara after 5 years of tamoxifen treatment was more effective than not taking Femara following tamoxifen treatment. In fact, women who took Femara for 5 years after tamoxifen treatment were 11% less likely to have their cancer come back, or get cancer in their other breast, than were women who took a placebo for 5 years after tamoxifen treatment. (A placebo is a treatment that contains no active drug.)

In a study of women with advanced breast cancer, Femara was more effective than tamoxifen in shrinking their tumors and helping them to live for a longer length of time. For example, half of the women with advanced breast cancer who had first-line treatment with Femara went 9.4 months or more without their cancer spreading or getting worse. In comparison, half of the women who had first-line treatment with tamoxifen went 6 months or more without their cancer spreading or getting worse.

Off-label use for infertility

Femara is also used off-label to treat infertility. Off-label use is when a drug that’s approved to treat one condition is used to treat another condition. For more information about this use of Femara, see the section “Off-label use of Femara for infertility” below.

Femara tablets contain the active drug letrozole. Generic forms of Femara are available.

A generic drug is an exact copy of a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to cost less than brand-name drugs.

Femara can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Femara. These lists do not include all possible side effects.

For more information on the possible side effects of Femara, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs they have approved. If you would like to report to the FDA a side effect you’ve had with Femara, you can do so through MedWatch.

Mild side effects

The mild side effects of Femara that are more common* can include:

  • hot flashes
  • flushed skin
  • increased sweating
  • joint pain
  • weakness
  • edema (swelling), possibly in your ankles or feet
  • headache
  • dizziness
  • bone pain

The mild side effects of Femara that are less common** can include:

  • fatigue (lack of energy)
  • nausea
  • vaginal bleeding or spotting
  • changes in your mood

* Occurred in more than 20% of people in clinical studies

** Occurred in 20% or less of people in clinical studies

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Femara aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects, which are explained in more detail below in “Side effect details,” include:

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on several of the side effects this drug cause.

In the following sections, certain side effects are described that occurred in clinical trials in women with either early or advanced breast cancer.

With early breast cancer, the cancer hasn’t spread out of either your breast or the lymph nodes in your armpit. But with advanced breast cancer, the cancer has spread to nearby areas or lymph nodes (called locally advanced breast cancer), or it has spread to other parts of the body (called metastatic breast cancer).

Reduced bone mineral density

Femara may cause reduced bone mineral density (weakened bones) in some people.

Femara, which works by lowering your estrogen level, is prescribed for women who’ve gone through menopause. Estrogen helps to keep your bones strong. But after menopause, your estrogen levels fall, which can weaken your bones. And because Femara also lowers your estrogen level, the drug can add to this effect. This increases your risk of breaking a bone during Femara treatment.

One clinical study reported bone density-related side effects in people using adjuvant treatment of early breast cancer. (For adjuvant treatment, therapy is given to help lower the risk of breast cancer coming back after surgery.) The following results were seen at an 8-year follow-up after people had an average of 5 years of treatment:

  • bone fractures had occurred in 14.7% of women who took Femara, compared with 11.4% of women who took the cancer drug tamoxifen
  • osteoporosis (thin, weak bones) had occurred in 5.1% of women who took Femara, compared with 2.7% of women who took tamoxifen

Another clinical study reported bone density-related side effects in women using extended adjuvant treatment of early breast cancer. (For extended adjuvant treatment, therapy is given to help lower the risk of the breast cancer coming back after someone has had surgery and has taken a drug called tamoxifen for 5 years.) The following results were seen after 5 years of treatment:

  • bone fractures had occurred in 13.3% of women who took Femara, compared with 7.8% of women who took a placebo (no active drug)
  • osteoporosis had occurred in 14.5% of women who took Femara, compared with 7.8% of women who took a placebo

If you’re taking Femara, your doctor may want to measure your bone mineral density. This allows them to monitor how strong your bones are. If your bones become weak during treatment, your doctor may prescribe medication for you to help strengthen your bones.

There are also some things you can do to help minimize loss of bone strength while you’re taking Femara. These things include:

  • getting enough calcium and vitamin D (through diet or taking supplements)
  • doing weight-bearing exercises
  • avoiding smoking
  • avoiding drinking large amounts of alcohol

If you have questions about how Femara may affect your bone density, talk with your doctor.

Raised cholesterol levels

Femara may raise the level of fat (cholesterol) in your blood. And having a raised cholesterol level can increase your risk of heart attack and stroke.

While you’re taking Femara, your doctor may order blood tests to monitor your cholesterol level. If your cholesterol level becomes too high, your doctor may prescribe a medication for you to help lower the level.

In clinical studies of people with early breast cancer, 29% of women who took Femara needed to take cholesterol-lowering medications. In comparison, 20% of women who took the cancer drug tamoxifen needed this type of medication.

There are some things that you can do to help reduce your risk of increased cholesterol levels, such as:

  • avoiding smoking
  • exercising regularly
  • eating a healthy diet

If you have questions about how Femara may affect your cholesterol, talk with your doctor.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Femara. But it’s not known how often this occurs in people using Femara.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (warmth and redness in your skin)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have a severe allergic reaction to Femara. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Fatigue or dizziness

For some people, Femara may cause fatigue (lack of energy) or tiredness. The drug may also make you feel dizzy.

In a clinical study of people with early breast cancer, fatigue was reported in 9.6% of women who took Femara for 5 years. In comparison, fatigue was reported in 10.2% of women who took the cancer drug tamoxifen for 5 years. Also, in this study, dizziness was reported in 3.4% of women who took Femara and in 3.3% of women who took tamoxifen.

If you have fatigue or dizziness while you’re taking Femara, don’t drive or operate other machines. And talk with your doctor about ways to help improve your energy level during treatment.

Weight gain or weight loss

Your body weight may change while you’re taking Femara. During clinical studies, both weight gain and weight loss were reported in women who took Femara for breast cancer treatment.

In one study of people with early breast cancer, weight gain was reported in 12.9% of women taking Femara. In contrast, weight loss was reported in 5.7% of women taking the drug. On the other hand, in women taking the cancer drug tamoxifen, 15.4% had weight gain and 5.3% had weight loss.

In one study of first-line treatment of people with advanced breast cancer, weight loss was reported in 7% of women taking Femara. In comparison, weight loss was reported in 5% of women taking tamoxifen. Weight gain wasn’t reported in this study.

In a study of second-line treatment of advanced breast cancer, weight gain was reported in 2% of women taking Femara. In comparison, weight gain was reported in 9% of women taking megestrol, and in 3% of women taking aminoglutethimide. (Megestrol and aminoglutethimide are other breast cancer treatments.) Weight loss wasn’t reported in this study.

Both cancer and cancer treatments can often cause changes in appetite and body weight. If you’re concerned about weight changes while you’re taking Femara, talk with your doctor.

Headache

You might get headaches while you’re taking Femara. In clinical studies, headaches were reported in about 4% to 20% of women taking the drug. This rate varied depending on the type of cancer the women were having treatment for.

If you have headaches while you’re using Femara, talk with your doctor about ways to reduce your discomfort.

Spotting

It’s possible to have vaginal bleeding or spotting while you’re taking Femara. In one clinical study of women with early breast cancer, vaginal bleeding was reported in 5.3% of women taking Femara. In comparison, vaginal bleeding was reported in 13.1% of women taking the cancer drug tamoxifen.

If you have any vaginal bleeding while you’re taking Femara, talk with your doctor. They can check to see what’s causing your vaginal bleeding, and they’ll recommend whether you should continue using this drug.

Hair loss

Some people may have hair loss or hair thinning while taking Femara. In a clinical study of women with early breast cancer, hair loss was reported in 3.4% of women taking the drug. Hair loss was also reported in 3.4% of women taking the cancer drug tamoxifen.

If you’re concerned about hair loss during Femara treatment, talk with your doctor.

Nausea

You may have some nausea while you’re taking Femara. In a clinical study of people with early breast cancer, 11.6% of women taking Femara felt nauseous. In comparison, nausea was reported by 11.3% of women taking the cancer drug tamoxifen. In women with advanced breast cancer, nausea was reported by 17% of women taking either Femara or tamoxifen.

Talk with your doctor if you have nausea while you’re taking Femara. They can recommend ways to help reduce this side effect.

Side effects after stopping Femara

Stopping Femara treatment isn’t known to cause side effects. And this medication doesn’t need to be stopped gradually.

In certain situations, if Femara has stopped working for you, your doctor might ask you to stop taking the drug in order to cause a “withdrawal response.” This response is a hormonal shift that’s caused by stopping Femara.

In this case, stopping Femara can sometimes improve your breast cancer, rather than causing side effects. However, this particular treatment approach isn’t right for everyone.

If your doctor thinks Femara has stopped working for you, talk with them about whether stopping treatment could be beneficial for you.

The Food and Drug Administration (FDA) approves prescription drugs such as Femara to treat certain conditions. But sometimes Femara is used off-label for other conditions. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Femara is used off-label to treat infertility in women. It’s mainly used when infertility is caused by problems with ovulation (the release of eggs from your ovaries). The most common cause of ovulation problems that result in infertility is polycystic ovary syndrome (PCOS).* But Femara is also sometimes used to treat infertility that doesn’t have an obvious cause.

In all of these cases, Femara is used to treat infertility by inducing (causing) ovulation. For this use, you’ll take Femara for a few days after the start of your period. Doing this temporarily lowers your estrogen level.

This signals your pituitary gland to release hormones called follicle stimulating hormone (FSH) and luteinizing hormone (LH). These hormones stimulate an egg in your ovary to mature and be released from your ovary. This is how Femara causes ovulation. This use of the drug is called ovulation induction.

If you’re already ovulating before taking Femara, the drug may cause more eggs than usual to mature and be released from your ovaries. This condition is called controlled ovarian hyperstimulation, or superovulation.

* PCOS is a condition that causes hormone problems, irregular or skipped periods, and cysts on your ovaries. Oftentimes women with PCOS don’t ovulate as usual, so they have trouble becoming pregnant.

Effectiveness for infertility

Taking Femara can help you to become pregnant if you’re trying to conceive (TTC), by either having sexual intercourse or using intrauterine insemination (IUI). But actual success rates of Femara for achieving pregnancy or having live births depend on many factors. These include:

  • the cause of your infertility
  • your age
  • whether you’re using Femara with other fertility treatments

You’re more likely to have success with Femara treatment for infertility if your body isn’t already ovulating.

One clinical study from 2014 looked at using Femara in women whose infertility was caused by PCOS. The women took Femara for different numbers of treatment cycles, depending on their unique situation. In this study, ovulation occurred in 61.7% of all Femara treatment cycles. And 27.5% of women taking the drug had a baby.

A different study looked at women whose infertility didn’t have a known cause. The women took Femara for different numbers of treatment cycles, depending on their unique situations. Pregnancy was achieved in 22.4% of all Femara treatment cycles. And 18.7% of women in the study had a baby. In this study, Femara was less effective than the other infertility drugs included in the study, gonadotropin and clomiphene.

Dosage for infertility

The usual dosage of Femara for inducing ovulation is 2.5 mg taken by mouth once daily for 5 days. Your doctor may ask you to start taking the drug either on day 3 or day 5 of your menstrual cycle. (Day 1 of your menstrual cycle is the first day of your period.) If you’re not having periods when starting Femara, your doctor will recommend when you should start taking the drug.

Sometimes your doctor may recommend that you take a higher dosage of Femara, such as 5 mg or 7.5 mg daily for 5 days.

The highest dose of Femara for fertility treatment hasn’t been determined. One 2011 study looked at using doses higher than the current standard dose to treat infertility. But more research is needed to know whether higher doses of Femara are more effective than lower doses. Be sure to always take the dosage of Femara that’s prescribed by your doctor.

Side effects when using Femara for infertility

Examples of both mild and serious side effects that can occur when using Femara for infertility include:

  • dizziness
  • fatigue (lack of energy)
  • hot flashes
  • breast tenderness
  • mood swings
  • night sweats
  • nausea
  • vomiting
  • spotting (light vaginal bleeding between periods)
  • ovarian cysts
  • rarely, ovarian hyperstimulation syndrome (OHSS), which is when more eggs than usual develop in your ovaries

Side effect details

Here’s some detail on a few of the side effects this drug may or may not cause when it’s used to treat infertility.

Spotting or changes in your periods

Taking Femara for infertility shouldn’t affect your period. But some women have spotting (light vaginal bleeding between periods) either during or after Femara use.

In fact, some women have spotting just before or during ovulation. And spotting can also happen when a fertilized egg implants into the wall of the uterus.

If you have spotting after taking Femara, it could be a symptom of early pregnancy. However, spotting can also be a symptom of miscarriage or ectopic pregnancy. (With an ectopic pregnancy, a fertilized egg implants outside of your uterus. Ectopic pregnancies can sometimes be life threatening, if not treated right away.)

If you have any spotting or unusual bleeding after taking Femara, call your doctor right away. And if you have heavy bleeding or feel like you’re having a medical emergency, call 911.

Ovulation pain or cramping

Some women have mild twinges, cramping, or pain in their ovaries around the time of ovulation. But it’s not known if taking Femara makes this sort of pain more likely.

On rare occasions, your ovaries may become overstimulated by taking Femara. With hyperstimulation, more eggs than usual can develop in your ovaries. This is called ovarian hyperstimulation syndrome (OHSS). Symptoms of OHSS may include:

  • unusual pain, discomfort, or bloating in your belly or pelvic area
  • nausea and vomiting
  • feeling short of breath

Call your doctor right away if you have any symptoms of OHSS. Your doctor will check to see what’s causing your symptoms, and they’ll recommend treatment if needed.

Ovarian cysts

Taking Femara for infertility can sometimes cause cysts to develop on your ovaries. But it’s not known how often this occurs in people using the drug.

Your doctor may want to use ultrasound to check your ovaries for cysts before each treatment cycle of Femara. Tell your doctor if you develop any symptoms of ovarian cysts, which may include:

  • unusual pain, discomfort, or bloating in your belly or pelvic area
  • dull ache in your lower back or thighs
  • pain during sex

If you have any symptoms of ovarian cysts during Femara treatment, talk with your doctor. They can check to see what’s causing your symptoms. And they’ll recommend if you need any treatment.

How to take Femara for infertility

You’ll usually take Femara by mouth once daily for 5 days after the start of your menstrual cycle. Your doctor might ask you to take Femara on either cycle days 3 to 7 or cycle days 5 to 9. (Day 1 of your menstrual cycle is the first of your period.) Be sure to always take Femara exactly as your doctor recommends.

Ovulation tends to occur between 5 and 10 days after you’ve taken your last Femara tablet. Your doctor will usually recommend using an ovulation predictor test to help you know when you’re about to ovulate.

Your doctor will also advise when you should start having sex if you’re trying to conceive (TTC) naturally. Or if you’re using IUI, you doctor will recommend when you should go into the clinic for artificial insemination.

What’s the best time of day to take Femara for infertility?

You can take Femara at any time of day. But try to take it around the same time on each of the 5 days that you’re taking the drug.

How long can you take Femara for fertility treatment?

Most doctors won’t prescribe Femara for more than six cycles of treatment. This is because if you haven’t gotten pregnant after six treatment cycles, it’s likely that this drug won’t work for you.

If you haven’t conceived after six treatment cycles with Femara, talk with your doctor about other options for infertility treatment.

Femara vs. Clomid

Femara contains the active drug letrozole, while Clomid contains the active drug clomiphene. Clomid has been discontinued, but generic versions of clomiphene are still available.

Femara and clomiphene are both used to induce (cause) ovulation in women who are having trouble becoming pregnant. For these women, infertility may be caused by problems with ovulation, or it may not have an obvious cause (called unexplained infertility).

Femara is used off-label for this purpose. (Off-label use is when a drug that’s approved for one condition is used to treat another.) However, clomiphene is FDA-approved for treating infertility in women.

Femara and clomiphene work in slightly different ways in your body to induce ovulation. But both drugs are usually taken for 5 days at the start of your menstrual cycle.

Effectiveness of Femara and clomiphene

Whether Femara or clomiphene is more effective for you may depend on the cause of your infertility.

For example, a 2014 study found Femara to be more effective than clomiphene in treating infertility in women with PCOS. In this study, the women took either Femara or clomiphene for different numbers of treatment cycles, depending on their unique situation.

Ovulation occurred in 61.7% of all Femara treatment cycles. And ovulation occurred in 48.3% of all clomiphene treatment cycles. Of the women who took Femara, 27.5% had a baby. In comparison, 19.1% of women who took clomiphene had a baby. In this study, there were no significant differences in the rates of miscarriage or twin pregnancies seen in the two treatment groups.

A more recent review of studies also found Femara to be more effective than clomiphene in treating infertility in women with PCOS. Rates of pregnancy and live births were higher for women who took Femara than for women who took clomiphene. And this review also found that women who took Femara got pregnant faster than did those who took clomiphene.

Another recent review of studies found Femara and clomiphene to be similarly effective in treating unexplained infertility. This review found that just under 25% of women taking either drug conceived during treatment. And no differences were seen between the two treatment groups in the rates of live births, multiple pregnancies (such as twins or triplets), or miscarriage.

Alternatives for infertility

Many drugs are available to treat infertility. Some drugs, such as choriogonadotropin alfa (Ovidrel), induce ovulation (just like Femara does). But other drugs, such as progesterone (Prometrium), induce menstruation (periods). And there are other drugs used to treat infertility that do other things in your body.

If you’d like to know more about treatment options for infertility, talk with your doctor.

The Food and Drug Administration (FDA) approves prescription drugs such as Femara to treat certain conditions.

Femara is a hormone therapy that’s approved to treat certain forms of breast cancer in women who’ve gone through menopause.

Hormone therapies stop estrogen from encouraging breast cancer cells to grow. More specifically, Femara is a type of hormone therapy called an aromatase inhibitor. It works by stopping an enzyme (type of protein) called aromatase from working as usual. This enzyme is the main way that your body makes estrogen after you’ve gone through menopause.

Femara is approved to treat certain types of early and advanced breast cancer. See the sections “Femara for advanced breast cancer” and “Femara for adjuvant treatment of early breast cancer” below for more information.

Femara for advanced breast cancer

Femara is FDA-approved to treat advanced breast cancer that’s hormone receptor-positive (HR+). With advanced breast cancer, the cancer has spread to nearby areas or lymph nodes (called locally advanced breast cancer), or it has spread to other parts of the body (called metastatic breast cancer).

HR+ breast cancer is encouraged to grow by hormones, including estrogen. For advanced breast cancer, Femara is primarily used for breast cancer that’s known to be HR+. But because most breast cancers are HR+, Femara can also be used to treat advanced breast cancer whose HR status isn’t known.

Femara is used in the following ways to treat advanced breast cancer:

  • First-line treatment. With first-line treatment, Femara is the first drug given to treat the advanced breast cancer.
  • Second-line treatment. With second-line treatment, Femara is given to treat the advanced breast cancer after certain past therapy hasn’t worked. For this use, Femara can treat advanced breast cancer that has come back or spread after other treatments.

Effectiveness for advanced breast cancer

In several clinical studies, Femara was more effective than tamoxifen in treating breast cancer. (Tamoxifen is another hormone therapy drug that’s used to treat cancer.) In fact, aromatase inhibitors like Femara are recommended in current guidelines for people with HR+ breast cancer.

In a study of women with advanced breast cancer, Femara was more effective than tamoxifen in shrinking their tumors and helping them to live for a longer length of time. For example, half of the women with advanced breast cancer who had first-line treatment with Femara went 9.4 months or more without their cancer spreading or getting worse. In comparison, half of the women who had first-line treatment with tamoxifen went 6 months or more without their cancer spreading or getting worse.

Other studies have looked at using Femara as a second-line treatment for advanced breast cancer. These studies found that Femara was more effective than both megestrol and aminoglutethimide in treating the cancer. (These drugs are other hormone therapies used to treat cancer.) In fact, women taking Femara were less likely to have their advanced breast cancer worsen than were women taking either of these two other drugs.

Femara for adjuvant treatment of early breast cancer

Femara is FDA-approved for adjuvant treatment of early breast cancer that’s hormone receptor-positive (HR+). With early breast cancer, the cancer hasn’t spread out of either your breast or the lymph nodes in your armpit. HR+ breast cancer is encouraged to grow by hormones, including estrogen.

Adjuvant treatment of breast cancer is treatment that’s taken to reduce the risk of the cancer coming back after surgery. For this use, you’ll usually take the drug for 5 years following surgery to remove the cancer.

Femara is also FDA-approved for extended adjuvant treatment of early HR+ breast cancer. For this use, you’ll usually take Femara for 5 years after you’ve already taken tamoxifen for 5 years following surgery to remove the cancer.

Recent research found that using adjuvant treatment over a longer period of time could be even more beneficial. In one study, women who took Femara for an additional 5 years (10 years in total) went a 34% longer period of time without their cancer coming back or developing cancer in their other breast. This was compared to women who took a placebo (no active drug) for the additional 5 years.

However, after 5 years, the rate of overall survival wasn’t any higher in women who took Femara than in women who took the placebo. (Overall survival describes the length of time that people live after their condition is diagnosed or treatment is started.)

Talk with your doctor about how long you should take Femara for adjuvant treatment of breast cancer. Your doctor will help you to weigh potential risks and benefits of taking Femara for a long period of time. Risks of extended treatment to consider may include weakening of your bones or raised cholesterol levels.

Effectiveness for adjuvant treatment of early breast cancer

In several clinical studies, Femara was more effective than tamoxifen in treating breast cancer. (Tamoxifen is another hormone therapy drug that’s used to treat cancer.) In fact, aromatase inhibitors like Femara are recommended in current guidelines for people with HR+ breast cancer.

In studies of women with early breast cancer, Femara was more effective than tamoxifen was in preventing their breast cancer from coming back or spreading after surgery. In one study, women who took Femara for 5 years after surgery were 13% less likely to have their breast cancer come back or spread than were women who took tamoxifen for 5 years after surgery.

Another study showed that in women with early breast cancer, taking Femara after 5 years of tamoxifen treatment was more effective than not taking Femara following tamoxifen treatment. In fact, women who took Femara for 5 years after tamoxifen treatment were 11% less likely to have their cancer come back, or get cancer in their other breast, than were women who took a placebo for 5 years after tamoxifen treatment. (A placebo is a treatment that contains no active drug.)

Off-label uses for Femara

In addition to the uses listed above, Femara may be used off-label. Off-label drug use is when a drug that’s approved for one use is used for a different one that’s not approved. Below are examples of off-label uses for Femara.

Femara for infertility in women

Femara isn’t FDA-approved to treat infertility, but sometimes it’s used off-label for this purpose. For more information about using Femara for infertility, see the section “Off-label use of Femara for infertility” above.

Femara for infertility in men

Femara isn’t approved to treat infertility in men. However, it’s sometimes used off-label for this use. In addition, a small study found that Femara may be effective in treating infertility in men who have both obesity and low testosterone levels.

If you’re interested in using Femara for this purpose, talk with your doctor.

Femara for PCOS

Femara isn’t approved to treat polycystic ovary syndrome (PCOS). But sometimes the drug is used off-label to treat infertility in women with PCOS.

PCOS is a condition that causes hormone problems, irregular or skipped periods, and cysts on your ovaries. Oftentimes women with PCOS don’t ovulate like usual, so they have trouble becoming pregnant.

Femara induces (causes) ovulation and can increase your chances of becoming pregnant. For more information about using Femara to treat infertility, see the section “Off-label use of Femara for infertility” above.

If you’d like to know about using Femara for this purpose, talk with your doctor.

Femara for endometriosis

Femara isn’t approved to treat endometriosis. But sometimes the drug is used off-label in people with this condition.

With endometriosis, tissue that’s similar to the tissue lining your uterus grows in other parts of your body. This condition can become very painful and may lead to infertility in some people.

Some research from 2011 showed that Femara can help manage pain related to endometriosis. Femara is sometimes used off-label for this purpose in women who haven’t had success with other endometriosis treatments. It’s typically used in combination with a progestin hormone for this use.

Femara is also sometimes used off-label to treat infertility in women with endometriosis. Femara induces (causes) ovulation and can increase your chances of becoming pregnant. For more information about using Femara for infertility, see the section “Off-label use of Femara for infertility” above.

If you’d like to know about using Femara for these purposes, talk with your doctor.

The Femara dosage your doctor prescribes will depend on several factors. These include:

  • the condition you’re taking Femara to treat
  • how well your liver works

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Femara comes as 2.5-mg tablets that are taken by mouth.

Dosage for breast cancer

The usual dosage of Femara for breast cancer treatment is one tablet taken by mouth once each day.

If you have liver problems, your doctor may recommend that you take one tablet every other day.

In any case, your doctor will recommend how long to keep taking Femara.

Dosage for adjuvant treatment of breast cancer

The usual dosage of Femara for adjuvant treatment of breast cancer is one tablet taken by mouth once each day.

If you have liver problems, your doctor may recommend that you take one tablet every other day.

You should keep taking Femara for as long as your doctor recommends.

What if I miss a dose?

If you miss a dose of Femara, take it as soon as you remember, unless it’s almost time for your next dose. In that case, just skip the missed dose and take your next dose as scheduled. Don’t take two doses together to make up for a missed dose.

To help make sure that you don’t miss a dose, try setting a reminder on your phone. A medication timer may be useful, too.

Will I need to use this drug long term?

Femara is meant to be used as a long-term treatment for breast cancer. If you and your doctor determine that Femara is safe and effective for you, you’ll likely take it long term.

Here are answers to some frequently asked questions about Femara.

Is Femara a chemotherapy drug?

No, Femara isn’t a chemotherapy drug. Chemotherapy describes traditional drugs used to treat cancer. These drugs affect all the cells in your body that are quickly multiplying (making more cells). Cancer cells multiply quickly, but some healthy cells in your body also multiply quickly. This means that chemotherapy can affect both cancer cells and healthy cells.

Instead, Femara is a hormone therapy. It works by lowering the level of estrogen in your body. This helps slow the growth and spread of cancer that’s encouraged to grow by estrogen.

How long does Femara stay in your system?

Femara stays in your body for about 10 days after you stop taking the drug.

Can men with breast cancer take Femara?

Yes, Femara is sometimes used to treat breast cancer in men. But this is an off-label use of the drug. (With off-label use, a drug that’s approved to treat one condition is used to treat another condition.)

If you have questions about using Femara for this purpose, talk with your doctor.

Will I have withdrawal symptoms when I stop taking Femara?

No, you likely won’t. Withdrawal symptoms are side effects that can happen when you stop taking a drug that your body has become dependent on. (With dependence, your body needs the drug in order to feel normal.) Stopping Femara isn’t known to cause any withdrawal symptoms.

If you have questions about any symptoms after stopping Femara, talk with your doctor.

Other drugs are available that can treat breast cancer. Some may be a better fit for you than others. If you’re interested in finding an alternative to Femara, talk with your doctor. They can tell you about other medications that may work well for you.

Examples of other drugs that may be used to treat breast cancer include:

  • hormone therapies, other than Femara, such as:
  • targeted therapies, such as:
  • chemotherapy (traditional drugs used to treat cancer), such as:
    • doxorubicin (Adriamycin)
    • epirubicin (Ellence)
    • paclitaxel (Abraxane)
    • docetaxel (Taxotere)
    • capecitabine (Xeloda)
    • cyclophosphamide

You may wonder how Femara compares with other medications that are prescribed for similar uses. Here we look at how Femara and tamoxifen are alike and different.

Ingredients

Femara contains the active drug letrozole. Tamoxifen is a generic drug. It’s also available as the brand-name medication Soltamox.

Femara and tamoxifen are both hormone therapies that are approved to treat breast cancer. These drugs work by stopping the hormone estrogen from encouraging the cancer cells to grow and spread. But they each work in slightly different ways.

Femara is an aromatase inhibitor. It stops your body from making estrogen using the aromatase enzyme (type of protein). Tamoxifen, on the other hand, stops estrogen from attaching to cancer cells. These drugs are used in slightly different ways for breast cancer.

Uses

Femara is approved to treat breast cancer that’s hormone receptor-positive (HR+). This type of breast cancer is encouraged to grow by hormones, including estrogen. Femara can also be given to treat certain types of breast cancer whose hormone receptor status isn’t known. Femara is given to women who’ve gone through menopause.

This drug is prescribed for women with certain forms of either early or advanced breast cancer. With early breast cancer, the cancer hasn’t spread out of either your breast or the lymph nodes in your armpit. But with advanced breast cancer, the cancer has spread to nearby areas or lymph nodes (called locally advanced breast cancer), or it has spread to other parts of the body (called metastatic breast cancer).

Femara is used in the following ways for early HR+ breast cancer:

  • Adjuvant treatment. For this use, Femara is given to help lower the risk of the breast cancer coming back after surgery.
  • Extended adjuvant treatment. For this use, Femara is given to help lower the risk of the breast cancer coming back after it’s been treated with both surgery and 5 years of tamoxifen (another cancer drug).

Femara is used in the following ways for advanced breast cancer that’s either HR+ or whose hormone receptor status isn’t known:

  • First-line treatment. With first-line treatment, Femara is the first drug given to treat the advanced breast cancer.
  • Second-line treatment. With second-line treatment, Femara is given to treat the advanced breast cancer after certain past therapy hasn’t worked. For this use, Femara can treat advanced breast cancer that has come back or spread after other treatments.

Tamoxifen is approved for use in women, regardless of whether they’ve gone through menopause, and in men. This drug is used to:

  • lower the risk of early estrogen receptor-positive (ER+)* breast cancer from coming back or developing in the opposite breast after surgery (this use is called adjuvant treatment)
  • treat ER+ metastatic breast cancer
  • lower the risk of invasive breast cancer (cancer that grows into the breast tissue) following surgery and radiation in women with ductal carcinoma in situ (DCIS)**
  • help prevent breast cancer in women who have a high risk of developing the disease

* ER+ breast cancer has receptors (attachment sites) for estrogen, and it’s stimulated to grow by estrogen.

** DCIS is a type of cancer that’s made up of abnormal cells in the milk ducts of the breast. It is not yet invasive, which means it hasn’t spread outside the breast.

Drug forms and administration

Femara comes as tablets that are taken by mouth. Tamoxifen comes as both tablets and liquid that are taken by mouth.

Side effects and risks

Femara and tamoxifen can cause some similar and some different side effects. Below are examples of these side effects.

Mild side effects

These lists contain examples of mild side effects that can occur with Femara, with tamoxifen, or with both drugs (when taken individually).

  • Can occur with Femara:
    • headache
    • dizziness
    • fatigue (lack of energy)
    • bone pain
    • joint pain
    • weakness
  • Can occur with tamoxifen:
    • vaginal discharge
  • Can occur with both Femara and tamoxifen:
    • hot flashes
    • edema (swelling), possibly in your ankles or feet
    • vaginal bleeding or spotting
    • nausea
    • changes in your mood

Serious side effects

These lists contain examples of serious side effects that can occur with Femara, with tamoxifen, or with both drugs (when taken individually).

  • Can occur with Femara:
    • reduced bone mineral density (weakened bones), which may lead to osteoporosis (weak, thin bones)
  • Can occur with tamoxifen:
    • blood clots in your veins or lungs*
    • stroke*
    • changes in the lining of your uterus that could lead to uterine cancer*
    • liver problems, such as fatty liver, hepatitis (inflammation in your liver), or liver cancer
    • cataracts (cloudiness in the lens of your eye) or other eye problems
    • high calcium level in your blood
    • changes to your blood cell levels, such as low levels of either platelets or white blood cells
  • Can occur with both Femara and tamoxifen:
    • severe allergic reaction

* Tamoxifen has a boxed warning from the FDA regarding the risk of blood clots, stroke, and uterine cancer. A boxed warning is the strongest warning the FDA requires. It alerts doctors and patients about drug effects that may be dangerous.

Effectiveness

Femara and tamoxifen have different FDA-approved uses. But they’re both used for adjuvant treatment of early breast cancer and treatment of advanced breast cancer.

Femara has been found more effective than tamoxifen in treating early and advanced breast cancers in women who’ve gone through menopause.

In studies of women with early breast cancer, Femara was more effective than tamoxifen was in preventing their breast cancer from coming back or spreading after surgery. In one study, women who took Femara for 5 years after surgery were 13% less likely to have their breast cancer come back or spread than were women who took tamoxifen for 5 years after surgery.

In a clinical study of people with advanced breast cancer, Femara was more effective than tamoxifen in slowing down the worsening of people’s cancer. In this study, half of the women who took Femara went 9.4 months or more without their cancer spreading or getting worse. In comparison, half of the women who took tamoxifen went 6 months or more without their cancer spreading or getting worse.

Costs

Femara is a brand-name drug. It’s also available in generic form. Tamoxifen is a generic drug. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, Femara generally costs much more than tamoxifen. The actual price you’ll pay for either drug depends on your dose, your insurance plan, your location, and the pharmacy you use.

You may wonder how Femara compares with other medications that are prescribed for similar uses. Here we look at how Femara and Arimidex are alike and different.

Ingredients

Femara contains the active drug letrozole, while Arimidex contains the active drug anastrozole.

Uses

Femara and Arimidex are both approved for use in women who’ve gone through menopause. These drugs are used to treat breast cancer that’s hormone receptor-positive (HR+). This type of breast cancer is encouraged to grow by hormones, including estrogen. The drugs can also be used to treat certain types of breast cancer whose hormone receptor status isn’t known.

Both Femara and Arimidex are used as adjuvant treatment for early HR+ breast cancer. With early breast cancer, the cancer hasn’t spread out of either your breast or the lymph nodes in your armpit. For adjuvant treatment, either Femara or Arimidex is given to help lower the risk of the breast cancer coming back after it’s been treated with surgery.

In addition, Femara is also used as extended adjuvant treatment for HR+ early breast cancer. For this use, Femara is given to help lower the risk of the breast cancer coming back after it’s been treated with both surgery and 5 years of tamoxifen (another cancer drug).

Femara and Arimidex are also each used to treat advanced breast cancer. With advanced breast cancer, the cancer has spread to nearby areas or lymph nodes (called locally advanced breast cancer), or it has spread to other parts of the body (called metastatic breast cancer).

Both drugs are used in the following ways for advanced breast cancer that’s either HR+ or whose hormone receptor status isn’t known:

  • First-line treatment. With first-line treatment, either Femara or Arimidex is the first drug given to treat the advanced breast cancer.
  • Second-line treatment. With second-line treatment, either Femara or Arimidex is given to treat the advanced breast cancer after certain past therapy hasn’t worked. For this use, the drugs can treat advanced breast cancer that has come back or spread after other treatments. However, for this use, Arimidex is specifically approved to treat advanced breast cancer that has come back or spread after treatment with tamoxifen.

Drug forms and administration

Femara and Arimidex both come as tablets that are taken by mouth.

Side effects and risks

Femara and Arimidex are both aromatase inhibitors. Therefore, these medications can cause very similar side effects. Below are examples of these side effects.

Mild side effects

These lists contain examples of mild side effects that can occur with Femara, with Arimidex, or with both drugs (when taken individually).

  • Can occur with Femara:
    • changes in your mood
    • dizziness
    • fatigue (lack of energy)
    • vaginal bleeding or spotting
  • Can occur with Arimidex:
    • sore throat
    • cough
    • arthritis
    • body aches and pains
    • high blood pressure
    • feeling depressed
    • skin rash
    • shortness of breath
  • Can occur with both Femara and Arimidex:
    • hot flashes
    • increased sweating
    • headache
    • weakness
    • edema (swelling), possibly in your ankles or feet
    • nausea
    • bone pain
    • joint pain

Serious side effects

These lists contain examples of serious side effects that can occur with Arimidex or with both Arimidex and Femara (when taken individually).

  • Can occur with Femara:
    • no unique serious side effects
  • Can occur with Arimidex:
    • liver problems, such as hepatitis (liver inflammation)
    • serious skin problems, such as skin ulcers or blisters
  • Can occur with both Femara and Arimidex:
    • reduced bone mineral density (weakened bones), which may lead to osteoporosis (weak, thin bones)
    • severe allergic reaction

Effectiveness

Femara and Arimidex are both FDA-approved for use in women who’ve gone through menopause for adjuvant treatment of early breast cancer and treatment of advanced breast cancer.

One clinical study found these drugs to be similarly effective as adjuvant treatments of early breast cancer. And the American Cancer Society considers these drugs to be similarly effective in treating breast cancer.

Costs

Femara and Arimidex are both brand-name drugs. Generic forms of both Femara and Arimidex are available. Brand-name medications usually cost more than generics.

According to estimates on GoodRx.com, Femara costs significantly more than Arimidex. But the actual price you’ll pay for either drug depends on your insurance plan, your location, and the pharmacy you use.

Femara shouldn’t be taken during pregnancy. This is because both animal studies and reports of use by pregnant women suggest that Femara may cause birth defects and miscarriage. Also, keep in mind that Femara isn’t approved to treat breast cancer in women who haven’t gone through menopause yet.

If you think you could be pregnant, tell your doctor before you start taking Femara.

Femara’s effect on pregnancy when it’s used off-label for infertility

When Femara is used off-label to treat infertility, the drug doesn’t increase the risk of birth defects or miscarriage. It only has these risks if it’s taken when you’re already pregnant. (With off-label use, a drug that’s approved to treat one condition is used to treat another.)

When you take Femara to induce (cause) ovulation, the drug is cleared from your body within several days after you’ve stopped taking it. This means that Femara will no longer be in your body when you ovulate or conceive.

One study done in 2014 found no difference in the rates of birth defects between women who took Femara for infertility and women who conceived naturally. And another more recent study showed there was no difference in birth defects between women who used either Femara or clomiphene for infertility. (Clomiphene is usually the first treatment choice for infertility.)

If you have questions about the risks of Femara use in pregnancy, talk with your doctor.

Femara can cause birth defects and miscarriage if it’s taken during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re using Femara.

It’s not known if Femara passes into breast milk. But the drug could be harmful to a child who consumes it in breast milk. Because of this, you shouldn’t breastfeed while you’re taking Femara. And you should continue to avoid breastfeeding for at least 3 weeks after your last dose of the drug.

If you’re breastfeeding, talk with your doctor before you start taking Femara.

Femara is approved to treat certain types of breast cancer in women who’ve already gone through menopause.

What happens in breast cancer?

Breast cancer develops when cells in your breast tissue start to grow and multiply more quickly than usual. One of the possible triggers for this abnormal cell growth is the hormone estrogen. Breast cancers that are stimulated by hormones, such as estrogen, are called hormone receptor-positive (HR+). These cancers can be treated with hormone therapies that work by lowering estrogen levels in your body.

What does Femara do?

Femara is a hormone therapy that’s used for HR+ breast cancer. It’s a type of drug called an aromatase inhibitor. Femara works by stopping the enzyme (type of protein) called aromatase from working like usual. (Enzymes help chemical reactions in your body to happen.)

The aromatase enzyme helps make estrogen from other hormones called androgens. One example of an androgen is the hormone testosterone.

After you’ve gone through menopause, your ovaries no longer produce estrogen. At that point, the aromatase enzyme is the main pathway that your body uses to make estrogen. By stopping aromatase from working, Femara lowers the amount of estrogen in your body. This stops estrogen from being able to stimulate breast cancer cells to grow and multiply.

How long does it take to work?

Femara will start working soon after you start taking it. But you won’t be able to notice it working in your body. Your doctor may order tests from time to time to check and see if the drug is working for you. For example, they may order imaging tests to see if your cancer tumors are shrinking.

You should take Femara according to your doctor’s or healthcare provider’s instructions.

When to take

For breast cancer treatment, you’ll usually take Femara once each day. But if you have liver problems, your doctor may recommend that you take the drug once every other day.

You can take your dose at any time of the day. But try to always stick to the same time each day. To help make sure that you don’t miss a dose, try setting a reminder on your phone. A medication timer may be useful, too.

Taking Femara with food

You can take Femara with or without food.

Can Femara be crushed, split, or chewed?

No, Femara tablets should be swallowed whole. They shouldn’t be crushed, split, or chewed. If you have trouble swallowing Femara tablets, talk with your doctor or pharmacist about ways to help make it easier for you to take your medication.

Alcohol isn’t known to interact with Femara. However, if you find that Femara gives you a headache, or makes you feel dizzy, nauseous, or tired, drinking alcohol may worsen these side effects.

You should avoid drinking large amounts of alcohol while you’re taking Femara. This is because drinking a lot of alcohol can increase your risk of osteoporosis, which is already increased by the drug. (With osteoporosis, you have weak, thin bones.)

It’s also worth noting that alcohol is known to increase the risk of developing breast cancer. But it’s not known if drinking alcohol after you’re diagnosed with breast cancer can make your cancer worse or more likely to come back after treatment.

If you drink alcohol and you’re concerned about how this might affect your condition, talk with your doctor. They can recommend you how much alcohol is safe for you to drink during Femara treatment.

Femara can interact with some other medications. It can also interact with certain supplements as well as certain foods.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Femara and other medications

Below are lists of medications that can interact with Femara. These lists do not contain all the drugs that may interact with Femara.

Before taking Femara, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Femara and tamoxifen

Like Femara, tamoxifen is a hormone therapy drug that’s used to treat breast cancer. You shouldn’t take tamoxifen at the same time as you’re taking Femara. This is because doing so can make Femara less effective for you. However, if your doctor recommends, it’s fine to take Femara after you’ve finished taking tamoxifen.

If you have questions about using Femara and tamoxifen together, talk with your doctor.

Femara and drugs that contain estrogen

You shouldn’t take any drugs that contain estrogen with Femara. This is because doing so could make Femara less effective for you.

Examples of drugs that contain estrogen include:

If you have questions about using Femara with medications that contain estrogen, talk with your doctor.

Femara and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Femara.

However, it’s possible that certain plant-based estrogens (called phytoestrogens) could make Femara less effective for you. Phytoestrogens are supplements made from plants. They’re sometimes used by some women to help manage menopausal symptoms, such as hot flashes.

Always check with your doctor or pharmacist before using any herbs or supplement products while you’re taking Femara.

As with all medications, the cost of Femara can vary.

The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

Your insurance plan may require you to get prior authorization before approving coverage for Femara. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the request and let you and your doctor know if your plan will cover Femara.

If you’re not sure if you’ll need to get prior authorization for Femara, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Femara, help is available. Visit Medicine Assistance Tool to find programs that may help lower your cost of Femara.

Before taking Femara, talk with your doctor about your health history. Femara may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Allergy to Femara. You shouldn’t take Femara if you’ve ever had an allergic reaction to letrozole (the active drug in Femara) or to any of Femara’s inactive ingredients in the past. If you’re not sure about your medication allergies, talk with your doctor.
  • Liver problems. Femara is cleared from your body by your liver. If you have cirrhosis (liver scarring) or severe problems with your liver, you may need a lower dosage of Femara. For example, your doctor may recommend that you take Femara once every other day, instead of every day as usual. Talk with your doctor about any history of liver problems before starting Femara.
  • High cholesterol level. Femara can increase your cholesterol level. Because of this, you’ll have blood tests to check your cholesterol level while you’re taking the drug. If your cholesterol rises too high, you may need medication to lower it.
  • Osteoporosis. Taking Femara can weaken your bones. This can cause new or worsening osteoporosis (weak, thin bones). It can also increase your risk of bone fractures. Your doctor may measure your bone mineral density while you’re taking Femara. If you already have osteoporosis, or risk factors for developing this condition, you may need medication to help protect your bones during Femara treatment. (These risk factors include a family history of osteoporosis, limited physical activity, smoking, drinking alcohol, and not getting enough calcium or vitamin D.)
  • Pregnancy. Don’t take Femara if you’re pregnant. For more information about the risks of using this drug during pregnancy, please see the “Femara and pregnancy” section above.
  • Breastfeeding. Don’t take Femara if you’re breastfeeding. For more information, please see the “Femara and breastfeeding” section above.

Note: For more information about the potential negative effects of Femara, see the “Femara side effects” section above.

Taking more than the recommended dosage of Femara may result in overdose in some people. But it’s not known for sure what symptoms you may have from overdose.

What to do in case of overdose

If you think you’ve taken too much of this drug, call your doctor. You can also call the American Association of Poison Control Centers at 800-222-1222 or use their online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.

When you get Femara from the pharmacy, the pharmacist will add an expiration date to the label on the bottle. This date is typically 1 year from the date they dispensed the medication.

The expiration date helps guarantee that the medication is effective during this time. The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. If you have unused medication that has gone past the expiration date, talk to your pharmacist about whether you might still be able to use it.

Storage

How long a medication remains good can depend on many factors, including how and where you store the medication.

Femara tablets should be stored at room temperature (77°F/25°C) in a tightly sealed container. Avoid storing this medication in areas where it could get damp or wet, such as in bathrooms.

Disposal

If you no longer need to take Femara and have leftover medication, it’s important to dispose of it safely. This helps prevent others, including children and pets, from taking the drug by accident. It also helps keep the drug from harming the environment.

The FDA website provides several useful tips on medication disposal. You can also ask your pharmacist for information on how to dispose of your medication.

The following information is provided for clinicians and other healthcare professionals.

Indications

Femara is FDA-approved to treat breast cancer in postmenopausal women. It is indicated for use in the following ways:

  • adjuvant treatment of early hormone receptor-positive (HR+) breast cancer
  • extended adjuvant treatment of early HR+ breast cancer following 5 years of tamoxifen
  • first-line treatment of locally advanced or metastatic breast cancer that is HR+ or has an unknown hormone receptor status
  • as a second-line treatment for advanced breast cancer that is HR+ or has an unknown hormone receptor status

Mechanism of action

Femara contains letrozole, an aromatase inhibitor. Letrozole blocks the action of the aromatase enzyme, thereby preventing the conversion of androgens into estrogens. Estrogens are primarily produced by the aromatase enzyme in postmenopausal women.

HR+ breast cancers are stimulated to grow and spread through the action of hormones, including estrogen. Lowering estrogen levels in postmenopausal women by blocking aromatase can shrink HR+ tumors and slow the growth and spread of HR+ breast cancers.

Pharmacokinetics and metabolism

Food does not affect the absorption of letrozole. Steady state is achieved after 2 to 6 weeks of 2.5 mg daily dosing.

Letrozole is hepatically metabolized to an inactive metabolite that is cleared renally. About 90% of the dose is excreted in urine.

The terminal half-life of letrozole is approximately 2 days.

Age and renal impairment do not affect the pharmacokinetics of letrozole. However, severe hepatic impairment doubles the exposure to letrozole. Dosing every other day is recommended in people with cirrhosis or severe hepatic impairment (Child-Pugh class C).

Contraindications

Femara is contraindicated in:

  • women who are pregnant
  • people with known hypersensitivity to any ingredient of Femara

Storage

Femara should be stored at room temperature (77°F/25°C).

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.