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Premarin (Estrogens, Conjugated)
Conjugated estrogens bind to nuclear estrogen receptors in estrogen-responsive tissues, modulating gonadotropin secretion and reducing elevated LH and FSH in postmenopausal women.
PREMARIN is a conjugated estrogen mixture indicated for vasomotor symptoms, vulvar/vaginal atrophy, hypoestrogenism, metastatic breast cancer palliation, prostate cancer palliation, and osteoporosis prevention. The drug binds nuclear estrogen receptors to modulate gonadotropin secretion and reduce elevated LH/FSH in postmenopausal women. Significant contraindications include undiagnosed genital bleeding, breast cancer history, active thromboembolic disease, and hepatic impairment; CYP3A4 interactions may alter estrogen concentrations. Clinical use requires careful patient selection and monitoring given cardiovascular and cancer risks associated with hormone replacement therapy.
At a glance
| Generic name | Estrogens, Conjugated |
|---|---|
| Sponsor | Pfizer |
| Drug class | Estrogen replacement therapy |
| Target | Estrogen receptors (nuclear receptors) |
| Modality | Hormone therapy |
| Therapeutic area | Metabolic |
| Phase | FDA-approved |
| First approval | 1942 |
Mechanism of action
Endogenous estrogens are responsible for development and maintenance of the female reproductive system and secondary sexual characteristics. Estradiol is the principal intracellular human estrogen and substantially more potent than its metabolites estrone and estriol at the receptor level. Estrogens act through binding to nuclear receptors in estrogen-responsive tissues, with two estrogen receptors identified that vary in proportion by tissue. Circulating estrogens modulate pituitary secretion of gonadotropins (LH and FSH) through negative feedback mechanism, acting to reduce the elevated levels of these gonadotropins seen in postmenopausal women.
Approved indications
- Dyspareunia
- Menopausal flushing
Common side effects
- Headache
- Nasopharyngitis
- Upper respiratory tract infection
- Nausea
- Diarrhoea
Drug interactions
- CYP3A4 inducers (St. John's Wort, phenobarbital, carbamazepine, rifampin)
- CYP3A4 inhibitors (erythromycin, clarithromycin, ketoconazole, itraconazole, ritonavir, grapefruit juice)
- Medroxyprogesterone acetate (MPA)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| FDA label | Mechanism, indications, dosing, boxed warnings, drug interactions |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- Premarin CI brief — competitive landscape report
- Premarin updates RSS · CI watch RSS
- Pfizer portfolio CI