pharmacopeia
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Boxed warning

1. ESTROGENS HAVE BEEN REPORTED TO INCREASE THE RISK OF ENDOMETRIAL CARCINOMA Three independent case control studies have reported an increased risk of endometrial cancer in postmenopausal women exposed to exogenous estrogens for prolonged periods. 1-3 This risk was independent of the other known risk factors for endometrial cancer. These studies are further supported by the finding that incidence rates of endometrial cancer have increased sharply since 1969 in eight different areas of the United States with population-based cancer reporting systems, an increase which may be related to the rapidly expanding use of estrogens during the last decade. 4 The three case control studies reported that the risk of endometrial cancer in estrogen users was about 4.5 to 13.9 times greater than in nonusers. The risk appears to depend on both duration of treatment 1 and on estrogen dose. 3 In view of these findings, when estrogens are used for the treatment of menopausal symptoms, the lowest dose that will control symptoms should be utilized and medication should be discontinued as soon as possible. When prolonged treatment is medically indicated, the patient should be reassessed on at least a semiannual basis to determine the need for continued therapy.

Mechanism of action

Sourced from openFDA

Mechanism-of-action class: Estrogen Receptor Agonists.

Estrogen Receptor

Indications

Sourced from openFDA
  • ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE FULL STRENGTH and ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE HALF STRENGTH are indicated in the treatment of: Moderate to severe vasomotor symptoms associated with the menopause in those patients not improved by estrogens alone. (There is no evidence that estrogens are effective for nervous symptoms or depression without associated vasomotor symptoms, and they should not be used to treat such conditions.) ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE FULL STRENGTH and ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE HALF STRENGTH HAVE NOT BEEN SHOWN TO BE EFFECTIVE FOR ANY PURPOSE DURING PREGNANCY AND ITS USE MAY CAUSE SEVERE HARM TO THE FETUS (SEE BOXED WARNING ).ICD-10: N95.1

Contraindications

Sourced from openFDA
  • Estrogens should not be used in women with any of the following conditions: 1. Known or suspected cancer of the breast except in appropriately selected patients being treated for metastatic disease.contraindicated

Dosage & administration

Sourced from openFDA

1. Given cyclically for short-term use only: For treatment of moderate to severe vasomotor symptoms associated with the menopause in patients not improved by estrogen alone. The lowest dose that will control symptoms should be chosen and medication should be discontinued as promptly as possible. Administration should be cyclic (e.g., three weeks on and one week off). Attempts to discontinue or taper medication should be made at three to six month intervals. Usual Dosage Range 1 tablet of ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE FULL STRENGTH or 1 to 2 tablets of ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE HALF STRENGTH daily as recommended by the physician. Treated patients with an intact uterus should be monitored closely for signs of endometrial cancer and appropriate diagnostic measures should be taken to rule out malignancy in the event of persistent or recurring abnormal vaginal bleeding.

Warnings & precautions

Sourced from openFDA

Associated with Estrogens Induction of malignant neoplasms . Long term continuous administration of natural and synthetic estrogens in certain animal species increases this frequency of carcinomas of the breast, cervix, vagina, and liver. There is now evidence that estrogens increase the risk of carcinoma of the endometrium in humans (See Boxed Warning ). At the present time there is no satisfactory evidence that estrogens given to postmenopausal women increase the risk of cancer of the breast, 18 although a recent long-term follow-up of a single physician's practice has raised this possibility. 18a Because of the animal data, there is a need for caution in prescribing estrogens for women with a strong family history of breast cancer or who have breast nodules, fibrocystic disease, or abnormal mammograms. 2. Gallbladder disease . A recent study has reported a 2 to 3-fold increase in the risk of surgically confirmed gallbladder disease in women receiving postmenopausal estrogens, 18 similar to the 2-fold increase previously noted in users of oral contraceptives. 19-24a In the case of oral contraceptives the increased risk appeared after two years of use. 24 3. Effects similar to those caused by estrogen-progesterone oral contraceptives . There are several serious adverse effects of oral contraceptives, most of which have not, up to now, been documented as consequences of postmenopausal estrogen therapy. This may reflect the comparatively low doses of estrogen used in postmenopausal women.

Adverse reactions

Sourced from openFDA

Associated with Estrogens (See Warnings regarding induction of neoplasia, adverse effects on the fetus, increased incidence of gallbladder disease, and adverse effects similar to those of oral contraceptives, including thromboembolism). The following additional adverse reactions have been reported with estrogenic therapy, including oral contraceptives: Genitourinary system. Breakthrough bleeding, spotting, change in menstrual flow. Dysmenorrhea. Premenstrual-like syndrome. Amenorrhea during and after treatment. Increase in size of uterine fibromyomata. Vaginal candidiasis. Change in cervical erosion and in degree of cervical secretion. Cystitis-like syndrome. Breasts. Tenderness, enlargement, secretion. Gastrointestinal. Nausea, vomiting. Abdominal cramps, bloating. Cholestatic jaundice. Skin. Chloasma or melasma which may persist when drug is discontinued. Erythema multiforme. Erythema nodosum. Hemorrhagic eruption. Loss of scalp hair. Hirsutism. Eyes. Steepening of corneal curvature. Intolerance to contact lenses. CNS. Headache, migraine, dizziness. Mental depression. Chorea. Miscellaneous. Increase or decrease in weight. Reduced carbohydrate tolerance. Aggravation of porphyria. Edema. Changes in libido. Associated with Methyltestosterone A. Endocrine and Urogenital. 1. Female: The most common side effects of androgen therapy are amenorrhea and other menstrual irregularities, inhibition of gonadotropin secretion, and virilization, including deepening of the voice and clitoral enlargement. The latter usually is not reversible after androgens are discontinued.

Use in specific populations

Sourced from openFDA

G. Pregnancy Teratogenic Effects . Pregnancy Category X (see CONTRAINDICATIONS ).

Approval history

Sourced from openFDA
  • May 8, 1942NDANDA004782Wyeth Pharms
  • Dec 18, 1956NDANDA010402Wyeth Pharms
  • Oct 16, 1978NDANDA020216Wyeth Pharms
  • Nov 17, 1995NDANDA020527Wyeth Pharms
  • Oct 3, 2013NDANDA022247Wyeth Pharms
  • Oct 15, 2025ANDAANDA214023Novast Labs
  • Oct 15, 2025ANDAANDA214025Novast Labs

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
70,771 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Breast Cancer12,16717%
  2. 2Breast Cancer Female9,65314%
  3. 3Drug Ineffective4,2796.0%
  4. 4Nausea2,8394.0%
  5. 5Headache2,8014.0%
  6. 6Fatigue2,6573.8%
  7. 7Pain2,6423.7%
  8. 8Off Label Use2,4573.5%
  9. 9Breast Cancer Metastatic2,1353.0%
  10. 10Dizziness1,9962.8%
  11. 11Malaise1,9252.7%
  12. 12Dyspnoea1,8872.7%
  13. 13Depression1,8312.6%
  14. 14Anxiety1,7942.5%
  15. 15Diarrhoea1,7832.5%

Literature

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Recent PubMed references pinned to Estrogens as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 1,565 ClinicalTrials.gov registrations naming Estrogens as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Estrogens work?
Mechanism-of-action class: Estrogen Receptor Agonists.
What is Estrogens used for?
According to FDA labeling, Estrogens carries indications including: ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE FULL STRENGTH and ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE HALF STRENGTH are indicated in the treatment of: Moderate to severe vasomotor symptoms associated with the menopause in those patients not improved by estrogens alone. (There is no evidence that estrogens are effective for nervous symptoms or depression without associated vasomotor symptoms, and they should not be used to treat such conditions.) ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE FULL STRENGTH and ESTERIFIED ESTROGENS AND METHYLTESTOSTERONE HALF STRENGTH HAVE NOT BEEN SHOWN TO BE EFFECTIVE FOR ANY PURPOSE DURING PREGNANCY AND ITS USE MAY CAUSE SEVERE HARM TO THE FETUS (SEE BOXED WARNING ).. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Estrogens?
Estrogens is classified as Estrogen Receptor Agonists, Bone Formation Stimulation, Hematologic Activity Alteration, Pituitary Gland Activity Alteration, Vaginal Function Alteration.
What are the contraindications for Estrogens?
Estrogens labeling lists contraindications including: Estrogens should not be used in women with any of the following conditions: 1. Known or suspected cancer of the breast except in appropriately selected patients being treated for metastatic disease.. Always consult the full prescribing information and a clinician.
Note. Data for estrogens is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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