EVAMIST
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EVAMIST (EVAMIST).
Evamist (estradiol transdermal spray) is a form of estrogen hormone replacement therapy. Estrogens diffuse into target cells and bind to estrogen receptors, which then translocate to the nucleus and regulate gene transcription, leading to estrogenic effects.
| Metabolism | Estradiol is primarily metabolized in the liver via CYP3A4 and other cytochrome P450 enzymes. It is also metabolized in the gastrointestinal tract and skin. Major metabolites include estrone and estriol, which are conjugated (sulfates and glucuronides) and excreted in urine. |
| Excretion | Renal (90%) as metabolites; fecal (<5%); biliary (<1%) |
| Half-life | Terminal elimination half-life is 4 hours; clinical context: dosing every 6-8 hours maintains therapeutic levels |
| Protein binding | 80% bound to albumin and alpha-1-acid glycoprotein |
| Volume of Distribution | 3-5 L/kg; indicates extensive tissue distribution |
| Bioavailability | Intranasal: 70%; oral: not applicable (first-pass metabolism) |
| Onset of Action | Intranasal: 15-30 minutes; oral: not applicable |
| Duration of Action | 6-8 hours; clinical note: analgesic effect lasts approximately 6 hours, with peak at 1-2 hours |
1.53 mg per actuation (as estradiol hemihydrate); 1 spray to the inner forearm once daily.
| Dosage form | SPRAY |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (CrCl <30 mL/min); use with caution. |
| Liver impairment | Contraindicated in Child-Pugh Class B and C (moderate to severe hepatic impairment). No data for mild impairment; use with caution. |
| Pediatric use | Not indicated for use in pediatric patients. Safety and efficacy not established. |
| Geriatric use | No specific dose adjustment recommended; however, initiate at lowest effective dose due to increased risk of adverse effects (e.g., thromboembolism, malignancy) in elderly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for EVAMIST (EVAMIST).
| Breastfeeding | Estradiol is excreted in breast milk. The milk-to-plasma ratio is approximately 0.1-0.2. Studies show low concentrations in milk, but long-term effects on the infant are unknown. Evamist is not recommended during breastfeeding due to potential hormonal disruption and reduced milk production. |
| Teratogenic Risk | Evamist (estradiol transdermal spray) is contraindicated in pregnancy. First trimester exposure is associated with congenital anomalies including cardiovascular and limb defects. Second and third trimester exposure increases risk of urogenital abnormalities and potential long-term reproductive tract effects in offspring. Use is not recommended at any gestational stage. |
■ FDA Black Box Warning
Estrogen therapy increases the risk of endometrial cancer in women with an intact uterus. Use of unopposed estrogens is associated with an increased risk of endometrial hyperplasia and carcinoma. Additionally, estrogens should not be used to prevent cardiovascular disease or dementia. The Women's Health Initiative (WHI) study reported increased risks of stroke, deep vein thrombosis, pulmonary embolism, and breast cancer with estrogen-alone therapy.
| Common Effects | Cramps Abdominal distension Flatulence |
| Serious Effects |
["Undiagnosed abnormal genital bleeding","Known, suspected, or history of breast cancer","Known or suspected estrogen-sensitive neoplasia","Active or history of deep vein thrombosis or pulmonary embolism","Active or history of arterial thromboembolic disease (e.g., stroke, MI)","Known thrombophilic disorders (e.g., Protein C, S, or antithrombin deficiency)","Hepatic impairment or disease","Pregnancy","Hypersensitivity to estradiol or any ingredient"]
| Precautions | ["Risk of endometrial cancer: Use progestin in women with intact uterus.","Cardiovascular disorders: Increased risk of stroke, DVT, pulmonary embolism, especially in smokers and older women.","Breast cancer: Increased risk with long-term use.","Dementia: Increased risk in women ≥65 years old.","Gallbladder disease.","Hypercalcemia in patients with breast cancer and bone metastases.","Retinal vascular thrombosis: Discontinue if sudden vision loss occurs.","Fluid retention: Use with caution in patients with conditions exacerbated by edema.","Hypothyroidism: May need increased thyroid replacement dose.","Hepatic impairment: Contraindicated in severe liver disease."] |
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| Fetal Monitoring | No routine monitoring recommended as drug is contraindicated in pregnancy. If inadvertent exposure occurs, monitor for signs of early pregnancy disruption (e.g., vaginal bleeding) and consider fetal ultrasound to assess for structural anomalies. |
| Fertility Effects | Evamist may suppress ovulation at higher doses due to negative feedback on gonadotropins. Low-dose topical estradiol typically does not impair fertility but may affect endometrial receptivity. Use in women attempting conception is not recommended unless specifically prescribed for controlled ovarian stimulation protocols. |