Estrogens (Conjugated/Equine, Topical)Pronunciation
(ES troe jenz KON joo gate ed, EE kwine)
- Conjugated Estrogen
- Estrogenic Substances, Conjugated
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Premarin: 0.625 mg/g (30 g) [contains benzyl alcohol, cetyl alcohol, propylene glycol monostearate]
Brand Names: U.S.
- Estrogen Derivative
Conjugated estrogens contain a mixture of estrone sulfate, equilin sulfate, 17 alpha-dihydroequilin, 17 alpha-estradiol and 17 beta-dihydroequilin. Estrogens are responsible for the development and maintenance of the female reproductive system and secondary sexual characteristics. Estradiol is the principle intracellular human estrogen and is more potent than estrone and estriol at the receptor level; it is the primary estrogen secreted prior to menopause. Following menopause, estrone and estrone sulfate are more highly produced. Estrogens modulate the pituitary secretion of gonadotropins, luteinizing hormone, and follicle-stimulating hormone through a negative feedback system; estrogen replacement reduces elevated levels of these hormones in postmenopausal women.
Systemic absorption occurs
Hepatic via CYP3A4; estradiol is converted to estrone and estriol; also undergoes enterohepatic recirculation (avoided with vaginal administration); estrone sulfate is the main metabolite in postmenopausal women
Urine (primarily estriol, also as estradiol, estrone, and conjugates)
Time to Peak
Total estrone: 6 hours
Binds to sex-hormone-binding globulin and albumin
Use: Labeled Indications
Vulvar and vaginal atrophy associated with menopause: Treatment of atrophic vaginitis and kraurosis vulvae and moderate-to-severe dyspareunia (pain during intercourse) due to vaginal/vulvar atrophy of menopause
Angioedema, anaphylactic reaction or hypersensitivity to conjugated estrogens or any component of the formulation; undiagnosed abnormal genital bleeding; DVT or PE (current or history of); active or history of arterial thromboembolic disease (eg, stroke, MI); breast cancer (known, suspected, or history of); estrogen-dependent tumor (known or suspected); hepatic dysfunction or disease; known protein C, protein S, antithrombin deficiency or other known thrombophilic disorders; pregnancy
Canadian labeling: Additional contraindications (not in US labeling): Endometrial hyperplasia; partial or complete vision loss due to ophthalmic vascular disease; migraine with or without aura
General dosing guidelines: When treating postmenopausal women, use estrogens for the shortest duration possible at the lowest effective dose consistent with treatment goals. Reevaluate patients as clinically appropriate to determine if treatment is still necessary. Consider use of an estrogen with a progestin in postmenopausal women with a uterus. Women who have had a hysterectomy generally do not need a progestin; however one may be needed if there is a history of endometriosis. Dosage needs to be adjusted based upon the patient's response.
Vulvar and vaginal atrophy associated with menopause:
Atrophic vaginitis, kraurosis vulvae: Adult females: Intravaginal: 0.5 g/day (range 0.5 to 2 g/day) administered cyclically (21 days on, 7 days off). Adjust dose based on patient response.
Moderate-to-severe dyspareunia due to menopause: Adult females: Intravaginal: 0.5 g twice weekly (eg, Monday and Thursday) or once daily cyclically (21 days on, 7 days off)
Refer to adult dosing.
Dosing: Renal Impairment
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied).
Dosing: Hepatic Impairment
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied). Use is contraindicated with hepatic dysfunction or disease.
Intravaginal: Using applicator provided by the manufacturer, insert cream deeply into vagina. Insertion should be as far as possible into the vagina without causing discomfort. Applicator calibrated in 0.5 g increments up to 2 g. To clean applicator, remove plunger from barrel. Wash with mild soap and warm water; do not boil or use hot water. Allow to dry thoroughly before putting back together.
Vaginal cream: Store at room temperature of 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).
Ajmaline: Estrogen Derivatives may enhance the adverse/toxic effect of Ajmaline. Specifically, the risk for cholestasis may be increased. Monitor therapy
Anastrozole: Estrogen Derivatives may diminish the therapeutic effect of Anastrozole. Avoid combination
Anthrax Immune Globulin (Human): Estrogen Derivatives may enhance the thrombogenic effect of Anthrax Immune Globulin (Human). Monitor therapy
Anticoagulants: Estrogen Derivatives may diminish the anticoagulant effect of Anticoagulants. More specifically, the potential prothrombotic effects of some estrogens and progestin-estrogen combinations may counteract anticoagulant effects. Management: Carefully weigh the prospective benefits of estrogens against the potential increased risk of procoagulant effects and thromboembolism. Use is considered contraindicated under some circumstances. Refer to related guidelines for specific recommendations. Consider therapy modification
Antidiabetic Agents: Hyperglycemia-Associated Agents may diminish the therapeutic effect of Antidiabetic Agents. Monitor therapy
Ascorbic Acid: May increase the serum concentration of Estrogen Derivatives. Monitor therapy
Bosentan: May decrease the serum concentration of CYP3A4 Substrates. Monitor therapy
C1 inhibitors: Estrogen Derivatives may enhance the thrombogenic effect of C1 inhibitors. Monitor therapy
Cannabis: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy
Chenodiol: Estrogen Derivatives may diminish the therapeutic effect of Chenodiol. Management: Monitor clinical response to chenodiol closely when used together with any estrogen derivative. Monitor therapy
CloZAPine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of CloZAPine. Monitor therapy
Corticosteroids (Systemic): Estrogen Derivatives may increase the serum concentration of Corticosteroids (Systemic). Monitor therapy
CYP1A2 Inducers (Strong): May increase the metabolism of CYP1A2 Substrates. Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
CYP3A4 Inducers (Moderate): May decrease the serum concentration of CYP3A4 Substrates. Monitor therapy
CYP3A4 Inducers (Strong): May increase the metabolism of CYP3A4 Substrates. Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
Cyproterone: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy
Dabrafenib: May decrease the serum concentration of CYP3A4 Substrates. Management: Seek alternatives to the CYP3A4 substrate when possible. If concomitant therapy cannot be avoided, monitor clinical effects of the substrate closely (particularly therapeutic effects). Consider therapy modification
Dantrolene: Estrogen Derivatives may enhance the hepatotoxic effect of Dantrolene. Monitor therapy
Deferasirox: May decrease the serum concentration of CYP3A4 Substrates. Monitor therapy
Dehydroepiandrosterone: May enhance the adverse/toxic effect of Estrogen Derivatives. Avoid combination
Enzalutamide: May decrease the serum concentration of CYP3A4 Substrates. Management: Concurrent use of enzalutamide with CYP3A4 substrates that have a narrow therapeutic index should be avoided. Use of enzalutamide and any other CYP3A4 substrate should be performed with caution and close monitoring. Consider therapy modification
Exemestane: Estrogen Derivatives may diminish the therapeutic effect of Exemestane. Avoid combination
Hemin: Estrogen Derivatives may diminish the therapeutic effect of Hemin. Avoid combination
Herbs (Estrogenic Properties): May enhance the adverse/toxic effect of Estrogen Derivatives. Monitor therapy
Hyaluronidase: Estrogen Derivatives may diminish the therapeutic effect of Hyaluronidase. Management: Patients receiving estrogens (particularly at larger doses) may not experience the desired clinical response to standard doses of hyaluronidase. Larger doses of hyaluronidase may be required. Consider therapy modification
Immune Globulin: Estrogen Derivatives may enhance the thrombogenic effect of Immune Globulin. Monitor therapy
Indium 111 Capromab Pendetide: Estrogen Derivatives may diminish the diagnostic effect of Indium 111 Capromab Pendetide. Avoid combination
Lenalidomide: Estrogen Derivatives may enhance the thrombogenic effect of Lenalidomide. Monitor therapy
Mitotane: May decrease the serum concentration of CYP3A4 Substrates. Management: Doses of CYP3A4 substrates may need to be adjusted substantially when used in patients being treated with mitotane. Consider therapy modification
NSAID (COX-2 Inhibitor): May enhance the thrombogenic effect of Estrogen Derivatives. NSAID (COX-2 Inhibitor) may increase the serum concentration of Estrogen Derivatives. Monitor therapy
Ospemifene: Estrogen Derivatives may enhance the adverse/toxic effect of Ospemifene. Estrogen Derivatives may diminish the therapeutic effect of Ospemifene. Avoid combination
Pomalidomide: May enhance the thrombogenic effect of Estrogen Derivatives. Management: Canadian pomalidomide labeling recommends caution with use of hormone replacement therapy and states that hormonal contraceptives are not recommended. US pomalidomide labeling does not contain these specific recommendations. Consider therapy modification
ROPINIRole: Estrogen Derivatives may increase the serum concentration of ROPINIRole. Monitor therapy
Siltuximab: May decrease the serum concentration of CYP3A4 Substrates. Monitor therapy
Somatropin: Estrogen Derivatives may diminish the therapeutic effect of Somatropin. Shown to be a concern with oral hormone replacement therapy in postmenopausal women. Management: Monitor for reduced growth hormone efficacy. A larger somatropin dose may be required to reach treatment goal. This interaction does not appear to apply to non-orally administered estrogens (e.g., transdermal, vaginal ring). Consider therapy modification
St John's Wort: May decrease the serum concentration of CYP3A4 Substrates. Management: Consider an alternative for one of the interacting drugs. Some combinations may be specifically contraindicated. Consult appropriate manufacturer labeling. Consider therapy modification
Teriflunomide: May decrease the serum concentration of CYP1A2 Substrates. Monitor therapy
Thalidomide: Estrogen Derivatives may enhance the thrombogenic effect of Thalidomide. Monitor therapy
Theophylline Derivatives: Estrogen Derivatives may increase the serum concentration of Theophylline Derivatives. Exceptions: Dyphylline. Monitor therapy
Thyroid Products: Estrogen Derivatives may diminish the therapeutic effect of Thyroid Products. Monitor therapy
Tipranavir: Estrogen Derivatives may enhance the dermatologic adverse effect of Tipranavir. The combination of tipranavir/ritonavir and ethinyl estradiol/norethindrone was associated with a high incidence of skin rash. Tipranavir may decrease the serum concentration of Estrogen Derivatives. Management: Women using hormonal contraceptives should consider alternative, non-hormonal forms of contraception. Consider therapy modification
TiZANidine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of TiZANidine. Management: Avoid these combinations when possible. If combined use cannot be avoided, initiate tizanidine at an adult dose of 2 mg and increase in 2-4 mg increments based on patient response. Monitor for increased effects of tizanidine, including adverse reactions. Consider therapy modification
Tocilizumab: May decrease the serum concentration of CYP3A4 Substrates. Monitor therapy
Ursodiol: Estrogen Derivatives may diminish the therapeutic effect of Ursodiol. Monitor therapy
Reduced response to metyrapone test.
Due to systemic absorption, other adverse effects associated with systemic therapy may also occur. Frequency of adverse events reported with daily use.
1% to 10%:
Cardiovascular: Vasodilatation (4%)
Central nervous system: Pain (7%)
Gastrointestinal: Abdominal pain (8%)
Genitourinary: Mastalgia (6%), vaginitis (6%)
Neuromuscular & skeletal: Weakness (6%), back pain (5%)
<1% (Limited to important or life-threatening): Anaphylaxis, cerebrovascular accident, deep vein thrombosis, dementia, depression, endometrial carcinoma, gallbladder disease, gynecomastia, hypertension, leukorrhea, malignant neoplasm of breast, myocardial infarction, pulmonary embolism, retinal thrombosis, uterine fibroids (increase in size)
Concerns related to adverse effects:
• Anaphylaxis: Anaphylaxis requiring emergency medical management has been reported and may develop at any time during therapy (reported to occur within minutes to hours with oral therapy). Angioedema involving the face, feet, hands, larynx, and tongue has also been reported.
• Breast cancer: [US Boxed Warning]: Based on data from the Women’s Health Initiative (WHI) studies, an increased risk of invasive breast cancer was observed in postmenopausal women using conjugated estrogens (CE) in combination with medroxyprogesterone acetate (MPA). This risk may be associated with duration of use and declines once combined therapy is discontinued (Chlebowski 2009). The risk of invasive breast cancer was decreased in postmenopausal women with a hysterectomy using CE only, regardless of weight. However, the risk was not significantly decreased in women at high risk for breast cancer (family history of breast cancer, personal history of benign breast disease) (Anderson 2012).An increase in abnormal mammogram findings has also been reported with estrogen alone or in combination with progestin therapy. Estrogen use may lead to severe hypercalcemia in patients with breast cancer and bone metastases; discontinue estrogen if hypercalcemia occurs. Use is contraindicated in patients with known or suspected breast cancer.
• Dementia: [US Boxed Warning]: Estrogens with or without progestin should not be used to prevent dementia. In the Women’s Health Initiative Memory Study (WHIMS), an increased incidence of probable dementia was observed in women ≥65 years of age taking CE alone or in combination with MPA.
• Endometrial cancer: [US Boxed Warning]: The use of unopposed estrogen in women with a uterus is associated with an increased risk of endometrial cancer. The addition of a progestin to estrogen therapy may decrease the risk of endometrial hyperplasia, a precursor to endometrial cancer. Adequate diagnostic measures, including endometrial sampling if indicated, should be performed to rule out malignancy in postmenopausal women with undiagnosed abnormal vaginal bleeding. There is no evidence that the use of natural estrogens results in a different endometrial risk profile than synthetic estrogens at equivalent estrogen doses. The risk of endometrial cancer is dose and duration dependent; risk appears to be greatest with use ≥5 years and may persist following discontinuation of therapy. The use of a progestin is not generally required when low doses of estrogen are used locally for vaginal atrophy (NAMS 2012; NAMS 2013).
• Endometriosis: Estrogens may exacerbate endometriosis. Malignant transformation of residual endometrial implants has been reported posthysterectomy with unopposed estrogen therapy. Consider adding a progestin in women with residual endometriosis posthysterectomy.
• Inherited thrombophilia: Women with inherited thrombophilias (eg, protein C or S deficiency) may have increased risk of venous thromboembolism (DeSancho 2010; van Vlijmen 2011). Use is contraindicated in women with protein C, protein S, antithrombin deficiency, or other known thrombophilic disorders.
• Lipid effects: Estrogen compounds are generally associated with lipid effects such as increased HDL-cholesterol and decreased LDL-cholesterol. Triglycerides may also be increased in women with preexisting hypertriglyceridemia; discontinue if pancreatitis occurs.
• Ovarian cancer: Postmenopausal estrogens with or without progestins may increase the risk of ovarian cancer; however, the absolute risk to an individual woman is small. Although results from various studies are not consistent, risk does not appear to be significantly associated with the duration, route, or dose of therapy. In one study, the risk decreased after 2 years following discontinuation of therapy (Mørch 2009). Although the risk of ovarian cancer is rare, women who are at an increased risk (eg, family history) should be counseled about the association (NAMS 2012).
• Retinal vascular thrombosis: Estrogens may cause retinal vascular thrombosis; discontinue if migraine, loss of vision, proptosis, diplopia, or other visual disturbances occur; discontinue permanently if papilledema or retinal vascular lesions are observed on examination.
• Asthma: Use caution in patients with asthma; may exacerbate disease.
• Carbohydrate intolerance: May have adverse effects on glucose tolerance; use caution in women with diabetes.
• Cardiovascular disease: [US Boxed Warning]: Estrogens with or without progestin should not be used to prevent cardiovascular disease. Using data from the Women’s Health Initiative (WHI) studies, an increased risk of deep vein thrombosis (DVT) and stroke has been reported with CE and an increased risk of DVT, stroke, pulmonary emboli (PE) and myocardial infarction (MI) has been reported with CE with MPA in postmenopausal women 50 to 79 years of age. Additional risk factors include diabetes mellitus, hypercholesterolemia, hypertension, SLE, obesity, tobacco use, and/or history of venous thromboembolism (VTE). Risk factors should be managed appropriately; discontinue use if adverse cardiovascular events occur or are suspected. Use is contraindicated in women with active DVT, PE, active arterial thromboembolic disease or a history of these conditions.
• Diseases exacerbated by fluid retention: Use with caution in patients with diseases which may be exacerbated by fluid retention, including cardiac or renal dysfunction.
• Epilepsy: Use caution with epilepsy; may exacerbate disease.
• Gallbladder disease: Use of postmenopausal estrogen may be associated with an increased risk of gallbladder disease requiring surgery.
• Hepatic dysfunction: Estrogens are poorly metabolized in patients with hepatic dysfunction. Use caution with a history of cholestatic jaundice associated with prior estrogen use or pregnancy. Discontinue if jaundice develops or if acute or chronic hepatic disturbances occur. Use is contraindicated with hepatic impairment or disease.
• Hepatic hemangiomas: Use with caution in patients with hepatic hemangiomas.
• Hereditary angioedema: Exogenous estrogens may exacerbate angioedema symptoms in women with hereditary angioedema.
• Hypoparathyroidism: Use caution in patients with hypoparathyroidism; estrogen induced hypocalcemia may occur.
• Migraine: Use caution with migraine; may exacerbate disease.
• Porphyria: Use with caution in patients with porphyria; may exacerbate disease.
• SLE: Use with caution in patients with SLE; may exacerbate disease.
Concurrent drug therapy issues:
• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.
• Thyroid replacement therapy: Estrogens may increase thyroid-binding globulin (TBG) levels leading to increased circulating total thyroid hormone levels. Women on thyroid replacement therapy may require higher doses of thyroid hormone while receiving estrogens.
• Surgical patients: Whenever possible, estrogens should be discontinued at least 4 to 6 weeks prior to elective surgery associated with an increased risk of thromboembolism or during periods of prolonged immobilization.
Dosage form specific issues:
• Benzyl alcohol and derivatives: Some dosage forms may contain benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension and cardiovascular collapse (AAP ["Inactive" 1997]; CDC 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors 2001); avoid or use dosage forms containing benzyl alcohol with caution in neonates. See manufacturer’s labeling.
• Vaginal cream: Use of the vaginal cream may weaken latex found in condoms, diaphragms or cervical caps. Systemic absorption occurs following vaginal use; warnings, precautions, and adverse events observed with oral therapy should be considered.
• Laboratory changes: The use of estrogens and/or progestins may change the results of some laboratory tests (eg, coagulation factors, lipids, glucose tolerance, binding proteins). The dose, route, and the specific estrogen/progestin influences these changes. In addition, personal risk factors (eg, cardiovascular disease, smoking, diabetes, age) also contribute to adverse events; use of specific products may be contraindicated in women with certain risk factors.
• Risks vs benefits: [US Boxed Warning]: Estrogens with or without progestin should be used for the shortest duration possible at the lowest effective dose consistent with treatment goals and risks for the individual woman. Patients should be reevaluated as clinically appropriate to determine if treatment is still necessary. Available data related to treatment risks are from Women’s Health Initiative (WHI) studies, which evaluated oral CE 0.625 mg with or without MPA 2.5 mg relative to placebo in postmenopausal women. Other combinations and dosage forms of estrogens and progestins were not studied. Outcomes reported from clinical trials using CE with or without MPA should be assumed to be similar for other doses and other dosage forms of estrogens and progestins until comparable data becomes available.
• Vulvar and vaginal atrophy use: Moderate-to-severe symptoms of vulvar and vaginal atrophy include vaginal dryness, dyspareunia, and atrophic vaginitis. When used solely for the treatment of vulvar and vaginal atrophy, topical vaginal products should be considered. Use caution applying topical products to severely atrophic vaginal mucosa. Use of a progestin is normally not required when low-dose estrogen is applied locally and only for this purpose (NAMS 2012; NAMS 2013).
Routine physical examination that includes blood pressure and Papanicolaou smear, breast exam, mammogram. Monitor for signs of endometrial cancer in female patients with uterus. Adequate diagnostic measures, including endometrial sampling, if indicated, should be performed to rule out malignancy in all cases of undiagnosed abnormal genital bleeding. Monitor for loss of vision, sudden onset of proptosis, diplopia, migraine; signs and symptoms of thromboembolic disorders; glycemic control in patients with diabetes; lipid profiles in patients being treated for hyperlipidemias; thyroid function in patients on thyroid hormone replacement therapy.
Note: Monitoring of FSH and serum estradiol is not useful when managing symptoms associated with vulvar and vaginal atrophy.
In general, the use of estrogen and progestin as in combination hormonal contraceptives have not been associated with teratogenic effects when inadvertently taken early in pregnancy. These products are contraindicated for use during pregnancy. Use of the vaginal cream may weaken latex found in condoms, diaphragms, or cervical caps.
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Patient may experience hair loss, enlarged breasts, leg cramps, abdominal cramps, bloating, or dark patches on face. Have patient report immediately to prescriber signs of severe cerebrovascular disease (change in strength on one side is greater than the other, difficulty speaking or thinking, change in balance, or vision changes), signs of DVT (edema, warmth, numbness, change in color, or pain in the extremities), signs of liver problems (dark urine, fatigue, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or jaundice), signs of pancreatitis (severe abdominal pain, severe back pain, severe nausea, or vomiting), angina, shortness of breath, coughing up blood, severe headache, severe nausea, vomiting, severe dizziness, passing out, pelvic pain, vision changes, bulging eyes, contact lens discomfort, lump in breast, breast soreness or pain, nipple discharge, vaginal bleeding, vaginitis, severe vaginal irritation, depression, mood changes, edema, or memory impairment (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.
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