Conjugated estrogens and Estradiol interaction
Conjugated estrogens and Estradiol: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Conjugated estrogens (Premarin) label · effective 2025-05-30
(See CLINICAL STUDIES and WARNINGS, Probable Dementia and PRECAUTIONS, Geriatric Use .) In the absence of comparable data, these risks should be assumed to be similar for other doses of CE and other dosage forms of estrogens.
(See CLINICAL STUDIES and WARNINGS, Malignant Neoplasms, Breast cancer .) In the absence of comparable data, these risks should be assumed to be similar for other doses of CE and MPA, and other combinations and dosage forms of estrogens and progestins.
Free hormone concentrations, such as testosterone and estradiol, may be decreased.
Exacerbation of other conditions Estrogen therapy may cause an exacerbation of asthma, diabetes mellitus, epilepsy, migraine, porphyria, systemic lupus erythematosus, and hepatic hemangiomas and should be used with caution in women with these conditions.
From the Estradiol (Delestrogen) label · effective 2026-05-13
…increased risks of myocardial infarction, stroke, invasive breast cancer, pulmonary emboli, and deep vein thrombosis in postmenopausal women (50 to 79 years of age) during 5 years of treatment with oral conjugated estrogens (CE 0.625 mg) combined with medroxyprogesterone acetate (MPA 2.5 mg) relative to placebo [see CLINICAL PHARMACOLOGY , Clinical Studies ].
The Women’s Health Initiative Memory Study (WHIMS), a substudy of WHI, reported increased risk of developing probable dementia in postmenopausal women 65 years of age or older during 4 years of treatment with oral conjugated estrogens plus medroxyprogesterone acetate relative to placebo.
Other doses of oral conjugated estrogens with medroxyprogesterone acetate, and other combinations and dosage forms of estrogens and progestins were not studied in the WHI clinical trials and, in the absence of comparable data, these risks should be assumed to be similar.
Large doses of estrogen (5 mg conjugated estrogens per day), comparable to those used to treat cancer of the prostate and breast, have been shown in a large prospective clinical trial in men to increase the risks of nonfatal myocardial infarction, pulmonary embolism, and thrombophlebitis. b.
CARDIOVASCULAR AND OTHER RISKS Estrogens and progestins should not be used for the prevention of cardiovascular disease [see WARNINGS , Cardiovascular disorders ].
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.