Estradiol Gel

Divigel® (estradiol gel) 0.1% is a clear, colorless gel, which is odorless when dry. It is designed to deliver sustained circulating concentrations of estradiol when applied once daily to the skin. The gel is applied to a small area (200 cm²) of the thigh in a thin, quick-drying layer. Divigel® is available in three doses of 0.25, 0.5, and 1.0 g for topical application (corresponding to 0.25, 0.5, and 1.0 mg estradiol, respectively).

The active component of the topical gel is estradiol. Estradiol is a white crystalline powder, chemically described as estra-1,3,5(10)-triene-3,17β-diol. It has an empirical formula of C18H24O2 and molecular weight of 272.39. The structural formula is:

The remaining components of the gel (carbomer, ethanol, propylene glycol, purified water, and triethanolamine) are pharmacologically inactive.

See BOXED WARNINGS.

Cardiovascular Disorders

Estrogen-alone therapy has been associated with an increased risk of stroke and deep vein thrombosis (DVT).

Estrogen-plus progestin therapy has been associated with an increased risk of myocardial infarction as well as stroke, venous thrombosis and pulmonary embolism.

Should any of these occur or be suspected, estrogens should be discontinued immediately.

Risk factors for arterial vascular disease (e.g., hypertension, diabetes mellitus, tobacco use, hypercholesterolemia, and obesity) and/or venous thromboembolism (e.g., personal history or family history of VTE, obesity, and systemic lupus erythematosus) should be managed appropriately.

In the estrogen-alone substudy of the Women's Health Initiative (WHI), a statistically significant increased risk of stroke was observed in women receiving CE 0.625 mg daily compared to placebo (44 versus 32 per 10,000 women-years). The increase in risk was observed in year 1 and persisted. (See Clinical Studies.)

In the estrogen-plus-progestin substudy of the WHI study, a statistically significant increased risk of stroke was reported in women receiving CE/MPA 0.625 mg/2.5 mg daily compared to women receiving placebo (31 versus 24 per 10,000 women-years). The increase in risk was demonstrated after the first year and persisted.

In the estrogen-alone substudy of WHI, no overall effect on coronary heart disease (CHD) events (defined as non-fatal MI, silent MI, or death, due to CHD) was reported in women receiving estrogen-alone compared to placebo. (See Clinical Studies.)

In the estrogen-plus-progestin substudy of WHI, no statistically significant increase of CHD events was reported in women receiving CE/MPA compared to women receiving placebo (39 vs. 33 per 10,000 women-years). An increase in relative risk was demonstrated in year one and a trend toward decreasing relative risk was reported in years 2 through 5.

In postmenopausal women with documented heart disease (n=2,763, average age 66.7 years), a controlled clinical trial of secondary prevention of cardiovascular disease (Heart and Estrogen/Progestin Replacement Study (HERS)) treatment with CE/MPA (0.625 mg/2.5 mg per day) demonstrated no cardiovascular benefit. During an average follow-up of 4.1 years, treatment with CE/MPA did not reduce the overall rate of CHD events in postmenopausal women with established coronary heart disease. There were more CHD events in the CE/MPA-treated group than in the placebo group in year 1, but not during the subsequent years. Participation in an open label extension of the original HERS trial (HERS II) was agreed to by 2,321 women. Average follow-up in HERS II was an additional 2.7 years, for a total of 6.8 years overall. Rates of CHD events were comparable among women in the CE/MPA group and the placebo group in HERS, HERS II, and overall.

Large doses of estrogen (5 mg conjugated estrogens per day), comparable to those used to treat cancer of the prostate and breast, have been shown in a large prospective clinical trial in men to increase the risks of non-fatal myocardial infarction, pulmonary embolism, and thrombophlebitis.

In the estrogen-alone substudy of WHI the risk of VTE (DVT and pulmonary embolism [PE]), was reported to be increased for women taking conjugated estrogens compared to placebo (30 versus 22 per 10,000 women-years), although only the increased risk of DVT reached statistical significance (23 vs. 15 per 10,000 women-years). The increase in VTE risk was demonstrated during the first two years. (See Clinical Studies.)

In the estrogen-plus-progestin substudy of WHI, a statistically significant two-fold greater rate of VTE, was reported in women receiving CE/MPA compared to women receiving placebo (35 vs. 17 per 10,000 women-years). Statistically significant increases in risk for both DVT (26 vs. 13 per 10,000 women-years) and PE (18 vs. 8 per 10,000 women-years) were also demonstrated. The increase in VTE risk was demonstrated during the first year and persisted. (See Clinical Studies.)

If feasible, estrogens should be discontinued at least 4 to 6 weeks before surgery of the type associated with an increased risk of thromboembolism, or during periods of prolonged immobilization.

Malignant Neoplasms

The use of unopposed estrogens in women with intact uteri has been associated with an increased risk of endometrial cancer. The reported endometrial cancer risk among unopposed estrogen users is about 2 to 12 times greater than in non-users, and appears dependent on duration of treatment and on estrogen dose. Most studies show no significant increased risk associated with use of estrogens for less than 1 year. The greatest risk appears associated with prolonged use, with increased risk of 15- to 24-fold for 5 to 10 years or more. This risk has been shown to persist for at least 8 to 15 years after estrogen therapy is discontinued.

Clinical surveillance of all women taking estrogen/progestin combinations is important. Adequate diagnostic measures, including endometrial sampling when indicated, should be undertaken to rule out malignancy in all cases of undiagnosed persistent or recurring abnormal vaginal bleeding. There is no evidence that the use of natural estrogens results in a different endometrial risk profile than synthetic estrogens of equivalent estrogen dose. Adding a progestin to estrogen therapy has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer.

In some studies, the use of estrogens and progestins by postmenopausal women has been reported to increase the risk of breast cancer. The most important randomized clinical trial providing information about this issue is the Women's Health Initiative (WHI) (see Clinical Studies). The results from observational studies are generally consistent with those of the WHI clinical trial.

Observational studies have also reported an increased risk of breast cancer for estrogen-plusprogestin combination therapy, and a smaller increased risk for estrogen-alone therapy, after several years of use. For both findings, the excess risk increased with duration of use, and appeared to return to baseline over about five years after stopping treatment (only the observational studies have substantial data on risk after stopping). In these studies, the risk of breast cancer was greater, and became apparent earlier, with estrogen-plus-progestin

combination therapy as compared to estrogen-alone therapy. However, these studies have not found significant variation in the risk of breast cancer among different estrogens or among different estrogen-plus-progestin combinations, doses, or routes of administration. In the estrogen-alone substudy of WHI, after an average of 7.1 years of follow-up, CE (0.625 mg daily) was not associated with an increased risk of invasive breast cancer (RR 0.80, 95 % nCI 0.62-1.04).

In the estrogen-plus-progestin substudy, after a mean follow-up of 5.6 years, the WHI substudy reported an increased risk of breast cancer. In this substudy, prior use of estrogenalone or estrogen/progestin combination hormone therapy was reported by 26% of the women. The relative risk of invasive breast cancer was 1.24 (95% nCI, 1.01-1.54), and the absolute risk was 41 versus 33 cases per 10,000 women-years, for estrogen-plus-progestin compared with placebo, respectively. Among women who reported prior use of hormone therapy, the relative risk of invasive breast cancer was 1.86, and the absolute risk was 46 versus 25 cases per 10,000 women-years, for estrogen-plus-progestin compared with placebo. Among women who reported no prior use of hormone therapy, the relative risk of invasive breast cancer was 1.09, and the absolute risk was 40 versus 36 cases per 10,000 women-years for estrogen-plus-progestin compared with placebo. In the WHI trial, invasive breast cancers were larger and diagnosed at a more advanced stage in the estrogen-plusprogestin group compared with the placebo group. Metastatic disease was rare with no apparent difference between the two groups. Other prognostic factors such as histologic subtype, grade and hormone receptor status did not differ between the groups.

The use of estrogen-alone and estrogen-plus-progestin has been reported to result in an increase in abnormal mammograms requiring further evaluation.

All women should receive yearly breast examinations by a healthcare provider and perform monthly breast self-examinations. In addition, mammography examinations should be scheduled based on patient age, risk factors, and prior mammogram results.

Dementia

In the estrogen-alone Women's Health Initiative Memory Study (WHIMS), a substudy of WHI, a population of 2,947 hysterectomized women aged 65 to 79 years was randomized to CE (0.625 mg daily) or placebo. In the estrogen-plus-progestin WHIMS, a population of 4,532 postmenopausal women aged 65 to 79 years was randomized to CE/MPA (0.625 mg/2.5 mg daily) or placebo.

In the estrogen-alone substudy, after an average follow-up of 5.2 years, 28 women in the estrogen-alone group and 19 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for CE alone versus placebo was 1.49 (95% CI, 0.83-2.66). The absolute risk of probable dementia for CE alone versus placebo was 37 versus 25 cases per 10,000 women-years.

In the estrogen-plus-progestin substudy, after an average follow-up of 4 years, 40 women in the estrogen-plus-progestin group and 21 women in the placebo group were diagnosed with probable dementia. The relative risk of probable dementia for estrogen-plus-progestin versus placebo was 2.05 (95% CI, 1.21-3.48). The absolute risk of probable dementia for CE/MPA versus placebo was 45 versus 22 cases per 10,000 women-years.

When data from the two populations were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95% CI 1.19-2.60). Since both substudies were conducted in women aged 65 to 79 years, it is unknown whether these findings apply to younger postmenopausal women. (see BOXED WARNINGS and PRECAUTIONS, and Geriatric Use.)

Gallbladder Disease

A two- to four-fold increase in the risk of gallbladder disease requiring surgery in postmenopausal women receiving estrogens has been reported.

Hypercalcemia

Estrogen administration may lead to severe hypercalcemia in patients with breast cancer and bone metastases. If hypercalcemia occurs, use of the drug should be stopped and appropriate measures taken to reduce the serum calcium level.

Visual Abnormalities

Retinal vascular thrombosis has been reported in patients receiving estrogens. Discontinue medication pending examination if there is sudden partial or complete loss of vision, or a sudden onset of proptosis, diplopia, or migraine. If examination reveals papilledema or retinal vascular lesions, estrogens should be permanently discontinued.

ELESTRIN™
(estradiol) Gel

Read this PATIENT INFORMATION before you start using ELESTRIN and read what you get each time you refill your ELESTRIN prescription. There may be new information. This information does not take the place of talking to your healthcare provider about your menopausal symptoms or your treatment.

What is the most important information I should know about ELESTRIN (an estrogen hormone)?

• Using estrogen-alone may increase your chance of getting cancer of the uterus (womb)
  Report any unusual vaginal bleeding right away while you are using ELESTRIN. Vaginal bleeding after menopause may be a warning sign of cancer of the uterus (womb). Your healthcare provider should check any unusual vaginal bleeding to find out the cause.
• Do not use estrogen-alone to prevent heart disease, heart attacks, strokes, or dementia (decline in brain function)
• Using estrogen-alone may increase your chances of getting strokes or blood clots
• Using estrogen-alone may increase your chance of getting dementia, based on a study of women age 65 years or older
• Do not use estrogens with progestins to prevent heart disease, heart attacks, strokes or dementia
• Using estrogens with progestins may increase your chances of getting heart attacks, strokes, breast cancer, or blood clots
• Using estrogens with progestins may increase your chance of getting dementia, based on a study of women age 65 years or older
• You and your healthcare provider should talk regularly about whether you still need treatment with ELESTRIN

What is ELESTRIN?

ELESTRIN is a medicine in a colorless gel that contains an estrogen hormone (estradiol) which is absorbed through the skin into the bloodstream.

What is ELESTRIN used for?

ELESTRIN is used after menopause to:

• Reduce moderate to severe hot flashes

Estrogens are hormones made by a woman's ovaries. The ovaries normally stop making estrogens when a woman is between 45 to 55 years old. This drop in body estrogen levels causes the “change of life” or menopause (the end of monthly menstrual periods). Sometimes, both ovaries are removed during an operation before natural menopause takes place. The sudden drop in estrogen levels causes “surgical menopause.”

When the estrogen levels begin dropping, some women develop very uncomfortable symptoms, such as feelings of warmth in the face, neck, and chest, or sudden strong feelings of heat and sweating (“hot flashes” or “hot flushes”). In some women, the symptoms are mild, and they will not need estrogens. In other women, symptoms can be more severe. You and your healthcare provider should talk regularly about whether you still need treatment with ELESTRIN.

Who should not use ELESTRIN?

Do not start using ELESTRIN if you:

• Have unusual vaginal bleeding
• Currently have or have had certain cancers
  Estrogens may increase the chance of getting certain types of cancers, including cancer of the breast or uterus. If you have or have had cancer, talk with your healthcare provider about whether you should use ELESTRIN.
• Had a stroke or heart attack
• Currently have or have had blood clots
• Currently have or have had liver problems
• Have been diagnosed with a bleeding disorder
• Are allergic to ELESTRIN or any of its ingredients
  See the list of ingredients in ELESTRIN at the end of this leaflet
• Think you may be pregnant

Tell your healthcare provider:

• If you have any unusual vaginal bleeding
  Vaginal bleeding after menopause may be a warning sign of cancer of the uterus (womb). Your healthcare provider should check any unusual vaginal bleeding to find out the cause.
• About all of your medical problems
  Your healthcare provider may need to check you more carefully if you have certain conditions, such as asthma (wheezing), epilepsy (seizures), diabetes, migraine, endometriosis, lupus, or problems with your heart, liver, thyroid, kidneys, or have high calcium levels in your blood.
• About all the medicines you take
  This includes prescription and nonprescription medicines, vitamins, and herbal supplements. Some medicines may affect how ELESTRIN works. ELESTRIN may also affect how your other medicines work.
• If you are going to have surgery or will be on bed rest
  You may need to stop using ELESTRIN.
• If you are breastfeeding
  The hormone in ELESTRIN can pass into your breast milk.

How should I use ELESTRIN?

1. Start at the lowest dose and talk to your healthcare provider about how well that dose is working for you.
2. ELESTRIN should be used at the lowest dose possible for your treatment and only as long as needed. You and your healthcare provider should talk regularly (for example, every 3 to 6 months) about the dose you are taking and whether you still need treatment with ELESTRIN.

ELESTRIN comes in a metered-dose pump. One dose of ELESTRIN is released each time the pump is depressed (pressed down).

Use ELESTRIN exactly how your healthcare provider tells you.

The ELESTRIN pump contains enough of the medicine to let you prime the pump (get the pump ready) before you use it the first time. To prime the pump, push the head of the pump down slowly , then remove your finger from the pump head and allow it to spring back automatically (by itself). Repeat this until the gel comes out. Throw away this first amount of gel as it will not be a full dose. Once the pump head has come all the way back up, the pump is now primed and ready to use. With each dose, remember to push the pump head down slowly and allow it to spring back automatically let the pump head come all the way back up before you push it down again. If using more than 1 dose, wait 5 seconds before pumping the next dose. This will make sure that the pump works correctly and gives your full dose of ELESTRIN. Use the pump a total of 30 times (30 pushes) as your healthcare provider tells you. After you have initially primed the pump and have used a total of 30 doses of ELESTRIN, you will need to throw the pump away and use a new one. The correct amount of medicine in each dose cannot be assured after 30 doses have been used, even though the pump container is not completely empty.

Important things to remember when using ELESTRIN

Wash your hands with soap and water after applying the gel to reduce the chance that the medicine will be spread from your hands to other people.

Allow the gel to dry for five minutes or more before dressing. Try to keep the area dry for as long as possible.

Do not allow others to come in contact with the area of skin where you applied the gel for at least two hours after you apply ELESTRIN. Always move the spout into locked position and place the cap over the top of the pump after each use.

Never apply ELESTRIN to the breast. Never apply ELESTRIN in or around the vagina.

Do not allow others to apply the gel for you.

Do not apply sunscreen to the area where the gel was applied for at least 25 minutes.

Do not apply sunscreen to the area where the gel was applied for 7 or more consecutive days.

Avoid fire, flame or smoking until the gel has dried. ELESTRIN contains alcohol. Alcohol based gels are flammable.

It is important that you read and follow the detailed “Patient Instructions for Use” at the end of this leaflet on how to use the ELESTRIN pump and apply the dose.

What should I do if someone else is exposed to ELESTRIN?

If someone else is exposed to ELESTRIN by direct contact with the gel, that person should wash the area of contact with soap and water as soon as possible. The longer the gel is in contact with the skin before washing, the greater is the chance that the other person will absorb some of the estrogen hormone. This is especially important for men and children.

What should I do if I get ELESTRIN in my eyes?

If you get ELESTRIN in your eyes, rinse your eyes right away with warm clean water to flush out any ELESTRIN. Seek medical attention if needed.

What should I do if I miss a dose?

If you miss a dose, do not double the dose on the next day to catch up. If your next dose is less than 12 hours away, it is best just to wait and apply your normal dose the next day. If it is more than 12 hours until the next dose, apply the dose you missed and resume your normal dosing the next day.

What are the possible side effects of ELESTRIN?

Side effects are grouped by how serious they are and how often they happen when you are treated. Serious, but less common side effects include:

• Heart attack
• Stroke
• Blood clots
• Dementia
• Breast cancer
• Cancer of the lining of the uterus (womb)
• Cancer of the ovary
• High blood pressure
• High blood sugar
• Gallbladder disease
• Liver problems
• Enlargement of benign tumors of the uterus (“fibroids”)

Call your healthcare provider right away if you get any of the following warning signs or any other unusual symptoms that concern you:

• New breast lumps
• Unusual vaginal bleeding
• Changes in vision or speech
• Sudden new severe headaches
• Severe pains in your chest or legs with or without shortness of breath, weakness and fatigue

Less serious, but common side effects include:

• Headache
• Breast pain
• Irregular vaginal bleeding or spotting
• Stomach or abdominal cramps, bloating
• Nausea and vomiting
• Hair loss
• Fluid retention
• Vaginal yeast infection

These are not all the possible side effects of ELESTRIN. For more information, ask your healthcare provider or pharmacist for advice about side effects. You may report side effects to Meda Pharmaceuticals at 1-800-890-3098 or to FDA at 1-800-FDA-1088.

What can I do to lower my chances of a serious side effect with ELESTRIN?

• Talk with your healthcare provider regularly about whether you should continue using ELESTRIN
• If you have a uterus, talk to your healthcare provider about whether the addition of a progestin is right for you
  The addition of a progestin is generally recommended for a woman with a uterus to reduce the chance of getting cancer of the uterus. See your healthcare provider right away if you get vaginal bleeding while using ELESTRIN.
• Have a pelvic exam, breast exam and mammogram (breast X-ray) every year unless your healthcare provider tells you something else If members of your family have had breast cancer or if you have ever had breast lumps or an abnormal mammogram, you may need to have breast exams more often.
• If you have high blood pressure, high cholesterol (fat in the blood), diabetes, are overweight, or if you use tobacco, you may have a higher chance for getting heart disease
  Ask your healthcare provider for ways to lower your chances of getting heart disease.

General information about safe and effective use of ELESTRIN

Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not use ELESTRIN for conditions for which it was not prescribed. Do not give ELESTRIN to other people, even if they have the same symptoms you have. It may harm them.

Keep ELESTRIN out of the reach of children

This leaflet provides a summary of the most important information about ELESTRIN. If you would like more information, talk with your healthcare provider or pharmacist. You can ask for information about ELESTRIN that is written for health professionals. You can get more information by calling 1-800-890-3098 (toll free).

Patient Instructions for Use.

1. Remove the cap.

2. Activate the pump.

• Unlock the pump by turning the spout on top of the bottle a quarter turn to the left or the right.

3. Prime the pump (get the pump ready) before using the pump for the first time.

• Push the head of the pump down slowly and allow it to spring back automatically. Repeat this until gel comes out. Throw away the first amount of gel as it will not be a full dose. Once the pump head has come all the way back up, the pump is now primed and ready to use. Throw away the unused gel by placing it in the trash to avoid another person or pet from accidental contact with the gel or, eating or drinking it.
• After priming, the pump is ready to use.
• One complete pump depression will dispense the same amount of ELESTRIN each time. After each daily dose, return the spout to the locked position and replace the cap before you put it away.

4. Apply ELESTRIN.

• Dry skin completely before applying ELESTRIN

You should apply your daily dose of gel to clean, dry, unbroken skin. If you take a bath or shower or use a sauna, apply ELESTRIN after your bath, shower, or sauna. If you go swimming, try to leave as much time as possible, at least 2 hours, between applying your ELESTRIN dose and going into the water.

• Apply ELESTRIN at the same time each day.

Figure 1

To apply the dose, hold the pump with the tip facing the application area of the arm. For each pump depression needed, press the pump firmly and fully with a continuous motion without hesitation.

Figure 2

Gently spread the gel using only 2 fingers. Spread and gently rub in the gel over the entire area of your upper arm and shoulder area, as illustrated.

5. Wash your hands with soap and water.

ELESTRIN should not be used after the date printed on the container (expiration date).

What are the ingredients in ELESTRIN?

Active ingredient: estradiol.

Inactive ingredients: purified water, ethanol, propylene glycol, diethylene glycol monoethyl ether, carbomer 940, triethanolamine, and edetate disodium.

Treatment Of moderate To Severe Vasomotor Symptoms Due To Menopause

Treatment Of Moderate To Severe Symptoms Of Vulvar And Vaginal Aatrophy Due To Menopause

When prescribing solely for the treatment of moderate to severe symptoms of vulvar and vaginal atrophy due to menopause, topical vaginal products should be considered.

Dosage Forms And Strengths

EstroGel 0.06% is an estradiol transdermal gel. One pump depression delivers 1.25 g of gel that contains 0.75 mg estradiol.

EstroGel is a clear, colorless, hydroalcoholic 0.06 percent estradiol gel supplied in a non-aerosol, metered-dose pump. The pump consists of an LDPE inner liner encased in rigid plastic with a resealable polypropylene cap. Two pump sizes are available, a 50-gram (1.75 oz), and a 25-gram (0.88 oz). Each individually packaged 50-gram pump contains 50 grams of gel and is capable of delivering 32 metered 1.25-g doses. Each individually packaged 25-gram pump contains 25 grams of gel and is capable of delivering 14 metered 1.25-g doses. One pump depression (1.25 g EstroGel) contains 0.75 mg estradiol.

NDC: 17139-617-40............................. (50-gram pump)
NDC: 17139-617-20............................. (25-gram sample pump)

Storage And Handling

Keep out of reach of children.

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature].

Manufactured for: ASCEND Therapeutics® US, LLC, Herndon, VA 20170, By DPT Laboratories, San Antonio, TX 78215. Revised: 3/2014

EstroGel provides systemic estrogen therapy by releasing estradiol, the major estrogenic hormone secreted by the human ovary.

Mechanism Of Action

Endogenous estrogens are largely responsible for the development and maintenance of the female reproductive system and secondary sexual characteristics. Although circulating estrogens exist in a dynamic equilibrium of metabolic interconversions, estradiol is the principal intracellular human estrogen and is substantially more potent than its metabolites, estrone and estriol, at the receptor level.

The primary source of estrogen in normally cycling adult women is the ovarian follicle, which secretes 70 to 500 mcg of estradiol daily, depending on the phase of the menstrual cycle. After menopause, most endogenous estrogen is produced by conversion of androstenedione, secreted by the adrenal cortex, to estrone in the peripheral tissues. Thus, estrone and the sulfate-conjugated form, estrone sulfate, are the most abundant circulating estrogens in postmenopausal women.

Estrogens act through binding to nuclear receptors in estrogen-responsive tissues. To date, two estrogen receptors have been identified. These vary in proportion from tissue to tissue.

Circulating estrogens modulate the pituitary secretion of the gonadotropins, luteinizing hormone (LH) and FSH through a negative feedback mechanism. Estrogens act to reduce the elevated levels of these hormones seen in postmenopausal women.

Pharmacodynamics

There are no pharmacodynamic data for EstroGel.

Pharmacokinetics

Estradiol is transported across intact skin and into the systemic circulation by a passive diffusion process. The rate of diffusion across the stratum corneum is the rate-limiting factor. When EstroGel is applied to the skin, it dries in 2 to 5 minutes.

EstroGel 1.25 g (containing 0.75 mg of estradiol) was administered to 24 postmenopausal women once daily on the posterior surface of 1 arm from wrist to shoulder for 14 consecutive days. Mean maximal serum concentrations of estradiol and estrone on Day 14 were 46.4 pg/mL and 64.2 pg/mL, respectively. The time-averaged serum estradiol and estrone concentrations over the 24-hour dose interval after administration of 1.25 g EstroGel on Day 14 are 28.3 pg/mL and 48.6 pg/mL, respectively. Mean concentration-time profiles for unadjusted estradiol and estrone on Day 14 are shown in Figure 1.

FIGURE 1: Mean Serum Concentration - time Profiles for Unadjusted Estradiol and Estrone After Multiple- dose Application of 1.25g ExtroGel 0.06% for 14 Days

The serum concentrations of estradiol following 2.5 g EstroGel applications (1.25 g on each arm from wrist to shoulder) appeared to reach steady state after the third daily application.

The distribution of exogenous estrogens is similar to that of endogenous estrogens. Estrogens are widely distributed in the body and are generally found in higher concentrations in the sex hormone target organs. Estrogens circulate in blood largely bound to SHBG and albumin.

Exogenous estrogens are metabolized in the same manner as endogenous estrogens. Circulating estrogens exist in a dynamic equilibrium of metabolic interconversions. These transformations take place mainly in the liver. Estradiol is converted reversibly to estrone, and both can be converted to estriol, which is a major urinary metabolite. Estrogens also undergo enterohepatic recirculation via sulfate and glucuronide conjugation in the liver, biliary secretion of conjugates into the intestine, and hydrolysis in the intestine followed by reabsorption. In postmenopausal women, a significant proportion of the circulating estrogens exist as sulfate conjugates, especially estrone sulfate, which serves as a circulating reservoir for the formation of more active estrogens. Although the clinical significance has not been determined, Estradiol from EstroGel does not go through first-pass liver metabolism.

Estradiol, estrone, and estriol are excreted in the urine along with glucuronide and sulfate conjugates.

The apparent terminal exponential half-life for estradiol was about 36 hours following administration of 1.25 g EstroGel.

No pharmacokinetic studies were conducted in special populations, including patients with renal or hepatic impairment.

The effect of application site washing on the serum concentrations of estradiol was determined in 24 healthy postmenopausal women who applied 1.25 g of EstroGel once daily for 14 consecutive days. Site washing 1 hour after the application resulted in a 22 percent mean decrease in average 24-hour serum concentrations of estradiol.

The effect of estradiol transfer was evaluated in 24 healthy postmenopausal women who topically applied 1.25 g of EstroGel once daily on the posterior surface of 1 arm from wrist to shoulder for a period of 14 consecutive days. On each day, 1 hour after gel application, a cohort of 24 non-dosed healthy postmenopausal females directly contacted the dosed cohort at the site of gel application for 15 minutes. No change in endogenous mean serum concentrations of estradiol was observed in the non-dosed cohort after direct skin-to-skin contact with subjects administered EstroGel.

The effect of sunscreen and moisturizer lotion on estradiol absorption from 0.06% estradiol topical gel was evaluated in a randomized, open-label, three-period crossover study in 42 healthy postmenopausal women. The study results showed that repeated daily application of sunscreen for 7 days at 1 hour after the administration of 0.06% estradiol topical gel decreased the mean AUC0-24h and Cmax of estradiol by 16%. Repeated daily application of moisturizer lotion for 7 days at 1 hour after the administration of 0.06% estradiol topical gel increased the mean AUC0-24h and Cmax of estradiol by 38% and 73%, respectively.

The effect of daily application of sunscreen/moisturizer lotion on estradiol absorption, when sunscreen/moisturizer lotion is applied before administration of 0.06% estradiol topical gel, was not studied.

Clinical Studies

Effects On Vasomotor Symptoms

In a placebo-controlled study, 145 postmenopausal women between 29 and 67 years of age (81.4 percent were White) were randomly assigned to receive 1.25 g of EstroGel (containing 0.75 mg of estradiol) or placebo gel for 12 weeks. Efficacy was assessed at 4 and 12 weeks of treatment. A statistically significant reduction in the frequency and severity of moderate to severe hot flushes was shown at Weeks 4 and 12. (See Table 2)

TABLE 2 : Mean Change from Baseline in the Number and Severity of Hot Flushes per Day, ITT Population, LOCF

Effects On Vulvar And Vaginal Atrophy

Results of the vaginal wall cytology showed a significant (P ≤ 0.001) increase from baseline in the percent of superficial epithelial cells at Week 12 for 1.25 g EstroGel. In contrast, no significant change from baseline was observed in the placebo group.

Women's Health Initiative Studies

The WHI enrolled approximately 27,000 predominantly healthy postmenopausal women in two substudies to assess the risks and benefits of daily oral CE (0.625 mg)-alone or in combination with MPA (2.5 mg) compared to placebo in the prevention of certain chronic diseases. The primary endpoint was the incidence of CHD (defined as nonfatal MI, silent MI, and CHD death), with invasive breast cancer as the primary adverse outcome. A “global index” included the earliest occurrence of CHD, invasive breast cancer, stroke, PE, endometrial cancer (only in the CE plus MPA substudy), colorectal cancer, hip fracture, or death due to other causes. These substudies did not evaluate the effects of CE-alone or CE plus MPA on menopausal symptoms.

The WHI estrogen-alone substudy was stopped early because an increased risk of stroke was observed, and it was deemed that no further information would be obtained regarding the risks and benefits of estrogen-alone in predetermined primary endpoints. Results of the estrogen-alone substudy, which included 10,739 women (average 63 years of age, range 50-79; 75.3 percent White, 15.1 percent Black, 6.1 percent Hispanic, 3.6 percent Other), after an average follow-up of 7.1 years are presented in Table 3.

TABLE 3 : Relative and Absolute Risk Seen in the Estrogen-Alone Substudy of WHIa

For those outcomes included in the WHI “global index” that reached statistical significance, the absolute excess risk per 10,000 women-years in the group treated with CE-alone was 12 more strokes, while the absolute risk reduction per 10,000 women-years was 7 fewer hip fractures.9 The absolute excess risk of events included in the “global index“ was a non-significant 5 events per 10,000 women-years. There was no difference between the groups in terms of all-cause mortality.

No overall difference for primary CHD events (nonfatal MI, silent MI and CHD death) and invasive breast cancer in women receiving CE-alone compared with placebo was reported in final centrally adjudicated results from the estrogen-alone substudy, after an average follow-up of 7.1 years. See Table 3.

Centrally adjudicated results for stroke events from the estrogen-alone substudy, after an average follow-up of 7.1 years, reported no significant difference in the distribution of stroke subtype or severity, including fatal strokes, in women receiving estrogen-alone compared to placebo. Estrogen-alone therapy increased the risk of ischemic stroke, and this excess risk was present in all subgroups of women examined.10 See Table 3.

Timing of initiation of estrogen-alone therapy relative to the start of menopause may affect the overall risk benefit profile. The WHI estrogen-alone substudy stratified by age showed in women 50 to 59 years of age a non-significant trend toward reduced risk for CHD [hazard ratio (HR) 0.63 (95 percent CI, 0.36-1.09)] and overall mortality [HR 0.71 (95 percent CI, 0.46-1.11)].

The WHI estrogen plus progestin substudy was stopped early. According to the predefined stopping rule, after an average follow-up of 5.6 years of treatment, the increased risk of invasive breast cancer and cardiovascular events exceeded the specified benefits included in the “global index.” The absolute excess risk of events included in the “global index” was 19 per 10,000 women-years.

For those outcomes included in the WHI “global index” that reached statistical significance after 5.6 years of follow-up, the absolute excess risks per 10,000 women-years in the group treated with CE plus MPA were 7 more CHD events, 8 more strokes, 10 more PEs, and 8 more invasive breast cancers, while the absolute risk reduction per 10,000 women-years were 6 fewer colorectal cancers and 5 fewer hip fractures.

Results of the CE plus MPA substudy, which included 16,608 women (average 63 years of age, range 50-79; 83.9 percent White, 6.8 percent Black, 5.4 percent Hispanic, 3.9 percent Other), are presented in Table 4. These results reflect centrally adjudicated data after an average follow-up of 5.6 years.

TABLE 4 : Relative and Absolute Risk Seen in the Estrogen Plus Progestin Substudy of WHI at an Average of 5.6 Yearsa,b

Timing of initiation of estrogen plus progestin therapy relative to the start of menopause may affect the overall risk benefit profile. The WHI estrogen plus progestin substudy stratified by age showed in women 50 to 59 years of age a non-significant trend toward reduced risk for overall mortality [HR 0.69 (95 percent CI, 0.44­1.07)].

Women's Health Initiative Memory Study

The WHIMS estrogen-alone ancillary study of WHI enrolled 2,947 predominantly healthy hysterectomized postmenopausal women 65 years of age and older (45 percent were 65 to 69 years of age, 36 percent were 70 to 74 years of age, and 19 percent were 75 years of age and older) to evaluate the effects of daily CE (0.625 mg)-alone on the incidence of probable dementia (primary outcome) compared to placebo.

After an average follow-up of 5.2 years, the relative risk of probable dementia for CE-alone versus placebo was 1.49 (95 percent CI, 0.83-2.66). The absolute risk of probable dementia for CE-alone versus placebo was 37 versus 25 cases per 10,000 women-years. Probable dementia as defined in the study included Alzheimer's disease (AD), vascular dementia (VaD) and mixed type (having features of both AD and VaD). The most common classification of probable dementia in the treatment group and the placebo group was AD. Since the ancillary study was conducted in women 65 to 79 years of age, it is unknown whether these findings apply to younger postmenopausal women [see WARNINGS AND PRECAUTIONS, and Use In Specific Populations].

The WHIMS estrogen plus progestin ancillary study enrolled 4,532 predominantly healthy postmenopausal women 65 years of age and older (47 percent were 65 to 69 years of age, 35 percent were 70 to 74 years of age, and 18 percent were 75 years of age and older) to evaluate the effects of daily CE (0.625 mg) plus MPA (2.5 mg) on the incidence of probable dementia (primary outcome) compared to placebo.

After an average follow-up of 4 years, the relative risk of probable dementia for CE plus MPA versus placebo was 2.05 (95 percent CI, 1.21-3.48). The absolute risk of probable dementia for CE plus MPA versus placebo was 45 versus 22 cases per 10,000 women-years. Probable dementia as defined in the study included AD, VaD and mixed type (having features of both AD and VaD). The most common classification of probable dementia in the treatment group and the placebo group was AD. Since the ancillary study was conducted in women 65 to 79 years of age, it is unknown whether these findings apply to younger postmenopausal women [see WARNINGS AND PRECAUTIONS, and Use in Specific Populations].

When data from the two populations were pooled as planned in the WHIMS protocol, the reported overall relative risk for probable dementia was 1.76 (95 percent CI, 1.19-2.60). Differences between groups became apparent in the first year of treatment. It is unknown whether these findings apply to younger postmenopausal women

[see WARNINGS AND PRECAUTIONS, and Use In Specific Populations].

REFERENCES

8. Shumaker SA, et al. Conjugated Equine Estrogens and Incidence of Probable Dementia and Mild Cognitive Impairment in Postmenopausal Women. JAMA. 2004;291:2947-2958.

9. Jackson RD, et al. Effects of Conjugated Equine Estrogen on Risk of Fractures and BMD in Postmenopausal Women With Hysterectomy: Results From the Women's Health Initiative Randomized Trial. J Bone Miner Res. 2006;21:817-828.

10. Hendrix SL, et al. Effects of Conjugated Equine Estrogen on Stroke in the Women's Health Initiative. Circulation. 2006;113:2425-2434.

If you are less than 12 hours late in using your medicine, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

• Bone Density Scan
• Dilation and Curettage (D&C)
• Endometrial Ablation
• Hormone Therapy
• Menopause
• Sex and Menopause (What to Expect)

Your pharmacist can provide more information about estradiol topical.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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The following serious adverse reactions are discussed elsewhere in the labeling:

• Cardiovascular Disorders [see BOXED WARNING, and WARNINGS AND PRECAUTIONS]
• Malignant Neoplasms [see BOXED WARNING, and WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

EstroGel was studied in 2 well-controlled, 12-week clinical trials. Incidence of adverse drug reactions ≥ 5 percent for 1.25 g EstroGel 0.06% and placebo is given in Table 1.

TABLE 1 : Incidence of Adverse Drug Reactions ≥ 5 Percent Occurrence in the EstroGel Treatment Group for the Intent-to-Treat Safety Population in 2 Well-controlled Clinical Studies (Expressed as Percent of Treatment Group)

In 2 controlled clinical trials, application site reactions were reported by 0.6 percent of patients who received 1.25 g of EstroGel. Other skin reactions, such as pruritus and rash, were also noted.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of EstroGel. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Endometrial cancer

Pain; tenderness; breast cancer

Deep vein thrombosis; myocardial ischemia; phlebitis

Nausea; abdominal distension; diarrhea; stomach discomfort

Alopecia; rash; pruritus; application site: dryness, pain, discoloration, reaction, rash

Retinal vein occlusion

Headache; dizziness; insomnia; hypoesthesia; meningioma; aphasia; bradyphrenia; paresthesia

Drug ineffective; hot flush; arthralgia; night sweats; drug effect decreased; pain in extremity; fatigue; weight increased; pain; hypersensitivity; dyspnea; malignant mesenchymoma; angioedema; hepatitis acute; face edema; accidental exposure; myoclonus; gait disturbance; flushing

Read the entire FDA prescribing information for EstroGel (Estradiol Gel)