Last reviewed 2026-04-20 · How we verify

Estrace (ESTRADIOL)

Estrace works by binding to estrogen receptors in the body, mimicking the effects of natural estrogen.

Estrace (Estradiol) is a small molecule estrogen medication originally developed by Bristol Myers Squibb and currently owned by Pfizer. It targets the estrogen receptor and is FDA-approved for various indications, including acne, prostatic carcinoma, and hormone replacement therapy. Estrace is available as a generic medication, with 26 manufacturers, and is off-patent. It has a short half-life of 1.7 hours and low bioavailability of 5%. As a result, it requires frequent dosing to maintain therapeutic levels.

At a glance

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 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, which is 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, t

Approved indications

• Acne vulgaris
• Advanced Prostatic Carcinoma
• Atrophic vaginitis
• Atrophic vulva
• Contraception
• Controlled ovarian stimulation
• Female hypogonadism syndrome
• Hormone replacement cycle in embryo transfer
• Menopausal flushing
• Metastatic Breast Carcinoma
• Metastatic Prostate Carcinoma
• Ovarian deficiency symptoms
• Postmenopausal osteoporosis
• Premenstrual dysphoric disorder
• Primary ovarian failure
• Urethral atrophy
• Vasomotor symptoms associated with menopausal disorder

Boxed warnings

• WARNING: CIGARETTE SMOKING AND SERIOUS CARDIOVASCULAR EVENTS Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive (COC) use. This risk increases with age, particularly in women over 35 years of age, and with the number of cigarettes smoked. For this reason, COCs, including Iclevia, are contraindicated in women who are over 35 years of age and smoke [see Contraindications (4) and Warnings and Precautions (5.1) ]. WARNING: CIGARETTE SMOKING AND SERIOUS CARDIOVASCULAR EVENTS See full prescribing information for complete boxed warning. Iclevia is contraindicated in women over 35 years old who smoke. ( 4 ) Cigarette smoking increases the risk of serious cardiovascular events from combination oral contraceptive (COC) use. ( 5.1 )

Common side effects

• Deep and superficial venous thrombosis
• Pulmonary embolism
• Thrombophlebitis
• Myocardial infarction
• Stroke
• Increase in blood pressure
• Ovarian cancer
• Endometrial hyperplasia
• Endometrial cancer
• Breast cancer
• Cholestatic jaundice
• Increased incidence of gallbladder disease

Drug interactions

• atazanavir
• darunavir
• fosamprenavir
• fosphenytoin
• lamotrigine
• letrozole
• levothyroxine sodium
• liothyronine
• methylphenobarbital
• nelfinavir
• phenobarbital
• phenytoin

Key clinical trials

• Menopausal Hormones and Sympathetic Activation (PHASE4)
• Capivasertib+Fulvestrant asTreatment for Locally Advanced(Inoperable) or Metastatic HR+/HER2- Breast Cancer in Chinese Patients (PHASE3)
• Targeted Therapy Directed by Genetic Testing in Treating Patients With Locally Advanced or Advanced Solid Tumors, The ComboMATCH Screening Trial (PHASE2)
• Romosozumab as an Adjunct to Physiologic Estrogen Replacement in Functional Hypothalamic Amenorrhea (PHASE3)
• Study of ECI830 Single Agent or in Combination in Patients With Advanced HR+/HER2- Breast Cancer and Other Advanced Solid Tumors (PHASE1,PHASE2)
• A Study of LOXO-783 in Patients With Breast Cancer/Other Solid Tumors (PHASE1)
• Efficacy and Safety of Tinengotinib Tablets Combined With Fulvestrant Injection in Patients With HR Positive and HER-2 Negative Recurrent or Metastatic Breast Cancer Who Have Failed Prior Treatment (PHASE2)
• Liquid-biopsy Informed Platform Trial to Evaluate CDK4/6-inhibitor Resistant ER+/HER2- Metastatic Breast Cancer (PHASE2)

Patents

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Estrace CI brief — competitive landscape report
• Estrace updates RSS · CI watch RSS
• Pfizer portfolio CI