estrogens, conjugated (USP) 2.5 MG Oral Tablet

INDICATIONS AND USAGE Conjugated estrogens tablets is a mixture of estrogens indicated for: •Treatment of Moderate to Severe Vasomotor Symptoms due to Menopause. ( 1.1 ) •Treatment of Moderate to Severe Vulvar and Vaginal Atrophy due to Menopause ( 1.2 ) •Treatment of Hypoestrogenism due to Hypogonadism, Castration or Primary Ovarian Failure ( 1.3 ) •Treatment of Breast Cancer (for Palliation Only) in Appropriately Selected Women and Men with Metastatic Disease ( 1.4 ) •Treatment of Advanced Androgen-Dependent Carcinoma of the Prostate (for Palliation Only) ( 1.5 ) •Prevention of Postmenopausal Osteoporosis ( 1.6 ) 1.1 Treatment of Moderate to Severe Vasomotor Symptoms due to Menopause 1.2 Treatment of Moderate to Severe Symptoms of Vulvar and Vaginal Atrophy due to Menopause Limitations of Use 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. 1.3 Treatment of Hypoestrogenism due to Hypogonadism, Castration or Primary Ovarian Failure 1.4 Treatment of Breast Cancer (for Palliation Only) in Appropriately Selected Women and Men with Metastatic Disease 1.5 Treatment of Advanced Androgen-Dependent Carcinoma of the Prostate (for Palliation Only) 1.6 Prevention of Postmenopausal Osteoporosis Limitations of Use When prescribing solely for the prevention of postmenopausal osteoporosis, therapy should only be considered for women at significant risk of osteoporosis and non-estrogen medication should be carefully considered.

DOSAGE AND ADMINISTRATION Generally, when estrogen therapy is prescribed for a postmenopausal woman with a uterus, a progestin should be considered to reduce the risk of endometrial cancer [see Boxed Warning ]. A woman without a uterus does not need progestin. In some cases, however, hysterectomized women with a history of endometriosis may need a progestin [see Warnings and Precautions (5.2, 5.16) ] . Use of estrogen-alone, or in combination with a progestin, should be with the lowest effective dose and for the shortest duration consistent with treatment goals and risks for the individual woman. Postmenopausal women should be re-evaluated periodically as clinically appropriate to determine if treatment is still necessary. Conjugated estrogens tablets may be taken without regard to meals. •Daily administration of 0.3 mg, 0.45 mg, and 0.625 mg ( 2.1 , 2.2 , 2.3 , 2.5 , 2.6 ) •Cyclic administration of 0.3 mg, and 0.625 mg ( 2.1 , 2.2 , 2.3 ) 2.1 Treatment of Moderate to Severe Vasomotor Symptoms due to Menopause Patients should be treated with the lowest effective dose. Generally, women should be started at 0.3 mg conjugated estrogens tablets daily. Subsequent dosage adjustment may be made based upon the individual patient response. This dose should be periodically reassessed by the healthcare provider. Conjugated estrogens tablets therapy may be given continuously, with no interruption in therapy, or in cyclical regimens (regimens such as 25 days on drug followed by 5 days off drug), as is medically appropriate on an individual basis. 2.2 Treatment of Moderate to Severe Symptoms of Vulvar and Vaginal Atrophy due to Menopause Patients should be treated with the lowest effective dose. Generally, women should be started at 0.3 mg conjugated estrogens tablets daily. Subsequent dosage adjustment may be made based upon the individual patient response. This dose should be periodically reassessed by the healthcare provider. Conjugated estrogens tablets therapy may be given continuously, with no interruption in therapy, or in cyclical regimens (regimens such as 25 days on drug followed by 5 days off drug), as is medically appropriate on an individual basis. 2.3 Treatment of Hypoestrogenism due to Hypogonadism, Castration, or Primary Ovarian Failure Conjugated estrogens tablets therapy should be initiated and maintained with the lowest effective dose to achieve clinical goals. Female hypogonadism: 0.3 mg or 0.625 mg daily, administered cyclically (e.g., three weeks on and one week off). Doses are adjusted depending on the severity of symptoms and responsiveness of the endometrium [ see Clinical Studies (14.4) ]. Female castration or primary ovarian failure: 1.25 mg daily, cyclically. Adjust dosage, upward or downward, according to severity of symptoms and response of the patient. For maintenance, adjust dosage to lowest level that will provide effective control. 2.4 Treatment of Breast Cancer (for Palliation Only) in Appropriately Selected Women and Men with Metastatic Disease Suggested dosage is 10 mg three times daily, for a period of at least three months. 2.5 Treatment of Advanced Androgen-Dependent Carcinoma of the Prostate (for Palliation Only) 2x0.625 mg to 4x0.625 mg three times daily. The effectiveness of therapy can be judged by phosphatase determinations as well as by symptomatic improvement of the patient. 2.6 Prevention of Postmenopausal Osteoporosis Conjugated estrogens tablets therapy may be given continuously, with no interruption in therapy, or in cyclical regimens (regimens such as 25 days on drug followed by 5 days off drug), as is medically appropriate on an individual basis. Patients should be treated with the lowest effective dose. Generally, women should be started at 0.3 mg conjugated estrogens tablets daily. Subsequent dosage adjustment may be made based upon the individual clinical and bone mineral density responses. This dose should be periodically reassessed by the healthcare provider.

WARNINGS AND PRECAUTIONS • Estrogens increase the risk of gallbladder disease ( 5.4 ) • Discontinue estrogen if severe hypercalcemia, loss of vision, severe hypertriglyceridemia or cholestatic jaundice occurs ( 5.5 , 5.6 , 5.10 , 5.11 ) • Monitor thyroid function in patients on thyroid replacement therapy ( 5.12 , 5.19 ) 5.1 Cardiovascular Disorders An increased risk of stroke and DVT has been reported with estrogen-alone therapy. An increased risk of PE, DVT, stroke and MI has been reported with estrogen plus progestin therapy. Should any of these events occur or be suspected, estrogen with or without progestin therapy should be discontinued immediately. Risk factors for arterial vascular disease (for example, hypertension, diabetes mellitus, tobacco use, hypercholesterolemia, and obesity) and/or venous thromboembolism (VTE) (for example, personal or family history of VTE, obesity, and systemic lupus erythematosus) should be managed appropriately. Stroke In the WHI estrogen-alone substudy, a statistically significant increased risk of stroke was reported in women 50 to 79 years of age receiving daily CE (0.625 mg)-alone compared to women in the same age group receiving placebo (45 versus 33 per 10,000 women-years). The increase in risk was demonstrated in Year 1 and persisted [see Clinical Studies (14.5) ] . Should a stroke occur or be suspected, estrogen-alone therapy should be discontinued immediately. Subgroup analyses of women 50 to 59 years of age suggest no increased risk of stroke for those women receiving CE (0.625 mg)-alone versus those receiving placebo (18 versus 21 per 10,000 women-years). 1 In the WHI estrogen plus progestin substudy, a statistically significant increased risk of stroke was reported in women 50 to 79 years of age receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women in the same age group receiving placebo (33 versus 25 per 10,000 women-years) [see Clinical Studies (14.5) ] . The increase in risk was demonstrated after the first year and persisted. 1 Should a stroke occur or be suspected, estrogen plus progestin therapy should be discontinued immediately. Coronary Heart Disease In the WHI estrogen-alone substudy, no overall effect on coronary heart disease (CHD) events (defined as nonfatal MI, silent MI, or CHD death) was reported in women receiving estrogen-alone compared to placebo 2 [see Clinical Studies (14.5)] . Subgroup analyses of women 50 to 59 years of age suggest a statistically non-significant reduction in CHD events (CE [0.625 mg]-alone compared to placebo) in women with less than 10 years since menopause (8 versus 16 per 10,000 women-years). 1 In the WHI estrogen plus progestin substudy, there was a statistically non-significant increased risk of CHD events reported in women receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women receiving placebo (41 versus 34 per 10,000 women-years). 1 An increase in relative risk was demonstrated in Year 1, and a trend toward decreasing relative risk was reported in years 2 through 5 [see Clinical Studies (14.5) ] . In postmenopausal women with documented heart disease (n = 2,763, average 66.7 years of age), in a controlled clinical trial of secondary prevention of cardiovascular disease (Heart and Estrogen/Progestin Replacement Study; HERS), treatment with daily CE (0.625 mg) plus MPA (2.5 mg) demonstrated no cardiovascular benefit. During an average follow-up of 4.1 years, treatment with CE plus MPA did not reduce the overall rate of CHD events in postmenopausal women with established CHD. There were more CHD events in the CE plus MPA‑treated group than in the placebo group in Year 1, but not during the subsequent years. Two thousand, three hundred and twenty-one (2,321) women from the original HERS trial agreed to participate in an open label extension of HERS, HERS II. 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 (0.625 mg) plus MPA (2.5 mg) group and the placebo group in HERS, HERS II, and overall. Venous Thromboembolism (VTE) In the WHI estrogen-alone substudy, the risk of VTE (DVT and PE), was increased for women receiving daily CE (0.625 mg)-alone compared to placebo (30 versus 22 per 10,000 women-years), although only the increased risk of DVT reached statistical significance (23 versus 15 per 10,000 women-years). The increase in VTE risk was demonstrated during the first 2 years 3 [see Clinical Studies (14.5) ] . Should a VTE occur or be suspected, estrogen-alone therapy should be discontinued immediately. In the WHI estrogen plus progestin substudy, a statistically significant 2-fold greater rate of VTE was reported in women receiving daily CE (0.625 mg) plus MPA (2.5 mg) compared to women receiving placebo (35 versus 17 per 10,000 women-years). Statistically significant increases in risk for both DVT (26 versus 13 per 10,000 women-years) and PE (18 versus 8 per 10,000 women-years) were also demonstrated. The increase in VTE risk was demonstrated during the first year and persisted 4 [see Clinical Studies (14.5) ] . Should a VTE occur or be suspected, estrogen plus progestin therapy should be discontinued immediately. 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. 5.2 Malignant Neoplasms Endometrial Cancer An increased risk of endometrial cancer has been reported with the use of unopposed estrogen therapy in a woman with a uterus. 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 to be associated with prolonged use, with increased risks of 15- to 24-fold for 5 to 10 years or more, and this risk has been shown to persist for at least 8 to 15 years after estrogen therapy is discontinued. Clinical surveillance of all women using estrogen-alone or estrogen plus progestin therapy is important. Adequate diagnostic measures, including directed or random endometrial sampling when indicated, should be undertaken to rule out malignancy in postmenopausal women with undiagnosed persistent or recurring abnormal genital 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 postmenopausal estrogen therapy has been shown to reduce the risk of endometrial hyperplasia, which may be a precursor to endometrial cancer. Breast Cancer The WHI substudy of daily CE (0.625 mg)-alone provided information about breast cancer in estrogen-alone users. In the WHI estrogen-alone substudy, after an average follow-up of 7.1 years, daily CE (0.625 mg)-alone was not associated with an increased risk of invasive breast cancer [relative risk (RR) 0.80] 5 [see Clinical Studies (14.5) ] . After a mean follow-up of 5.6 years, the estrogen plus progestin substudy reported an increased risk of invasive breast cancer in women who took daily CE plus MPA. In this substudy, prior use of estrogen-alone or estrogen plus progestin therapy was reported by 26% of the women. The relative risk of invasive breast cancer was 1.24, and the absolute risk was 41 versus 33 cases per 10,000 women-years, for CE plus MPA compared with placebo. 6 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 CE plus MPA 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 CE plus MPA compare

CONTRAINDICATIONS Conjugated estrogens tablets therapy is contraindicated in individuals with any of the following conditions: • Undiagnosed abnormal genital bleeding [see Warnings and Precautions ( 5.2 )] • Breast cancer or a history of breast cancer except in appropriately selected patients being treated for metastatic disease [see Warnings and Precautions ( 5.2 )] • Estrogen-dependent neoplasia [see Warnings and Precautions ( 5.2 )] • Active DVT, PE, or a history of these conditions [see Warnings and Precautions ( 5.1 )] • Active arterial thromboembolic disease (for example stroke and MI), or a history of these conditions [see Warnings and Precautions ( 5.1 )] • Known anaphylactic reaction or angioedema with conjugated estrogens tablets [see Warnings and Precautions ( 5.7 , 5.15 )] • Hepatic impairment or disease [see Warnings and Precautions ( 5.11 )] • Protein C, protein S or antithrombin deficiency, or other known thrombophilic disorders. •Undiagnosed abnormal genital bleeding ( 4 ) •Breast cancer or history of breast cancer except in appropriately selected patients being treated for metastatic diseases ( 4 , 5.2 ) •Estrogen-dependent neoplasia ( 4 , 5.2 ) •Active DVT, PE, or a history of these conditions ( 4 , 5.1 ) •Active arterial thromboembolic disease (for example, stroke and MI), or a history of these conditions ( 4 , 5.1 ) •Known anaphylactic reaction or angioedema with conjugated estrogens tablets ( 5.7 , 5.15 ) •Hepatic impairment or disease ( 4 , 5.11 ) •Protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders ( 4 )

CLINICAL PHARMACOLOGY 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 estrogen 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 follicle stimulating hormone (FSH), through a negative feedback mechanism. Estrogens act to reduce the elevated levels of these gonadotropins seen in postmenopausal women. Pharmacokinetics A. Absorption Conjugated estrogens are water-soluble and are well-absorbed through the skin, mucous membranes, and gastrointestinal tract after release from the drug formulation. B. Distribution 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 concentration in the sex hormone target organs. Estrogens circulate in the blood largely bound to sex hormone-binding globulin (SHBG) and albumin. C. Metabolism 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. D. Excretion Estradiol, estrone, and estriol are excreted in the urine along with glucuronide and sulfate conjugates. E. Special Populations No pharmacokinetic studies were conducted in special populations, including patients with renal or hepatic impairment. F. Drug Interactions Data from a single-dose drug-drug interaction study involving oral CE and MPA indicate that the pharmacokinetic dispositions of both drugs are not altered when the drugs are coadministered. No other clinical drug-drug interaction studies have been conducted with conjugated estrogens. In vitro and in vivo studies have shown that estrogens are metabolized partially by cytochrome P450 3A4 (CYP3A4). Therefore, inducers or inhibitors of CYP3A4 may affect estrogen drug metabolism. Inducers of CYP3A4, such as St. John's wort (Hypericum perforatum) preparations, phenobarbital, carbamazepine, and rifampin, may reduce plasma concentrations of estrogens, possibly resulting in a decrease in therapeutic effects and/or changes in the uterine bleeding profile. Inhibitors of CYP3A4, such as erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir and grapefruit juice, may increase plasma concentrations of estrogens and may result in side effects.