VAGIFEM

Clinical safety rating: caution

Comprehensive clinical and safety monograph for VAGIFEM (VAGIFEM).

How it works

Estradiol is a form of estrogen that binds to estrogen receptors, activating gene transcription and leading to various physiological effects. It replaces endogenous estrogen in postmenopausal women, alleviating symptoms of vaginal atrophy.

What the body does with it

Metabolism	Primarily hepatic via CYP3A4. Undergoes extensive first-pass metabolism when administered orally; however, vaginal administration reduces first-pass effect.
Excretion	Vagifem (estradiol) undergoes hepatic metabolism and renal excretion. Approximately 60-80% of a dose is excreted in urine as glucuronide and sulfate conjugates, with about 10-15% excreted in feces via biliary elimination. Unchanged estradiol is minimally excreted.
Half-life	The terminal elimination half-life of estradiol is approximately 2-3 hours. Due to enterohepatic recirculation, the effective half-life may be longer, and daily dosing maintains steady-state concentrations.
Protein binding	Estradiol is approximately 98% bound to sex hormone-binding globulin (SHBG) and albumin, with SHBG binding being of higher affinity.
Volume of Distribution	The volume of distribution for estradiol is approximately 1 L/kg (range 0.5-1.5 L/kg), indicating extensive distribution into tissues, particularly fat and reproductive organs.
Bioavailability	Vagifem has a bioavailability of approximately 5-10% via vaginal route due to first-pass hepatic metabolism. Oral bioavailability is less than 5%, but not relevant for this product.
Onset of Action	The onset of action for Vagifem (estradiol vaginal tablet) is 2-4 weeks for improvement in vaginal symptoms (e.g., dryness, dyspareunia). Systemic effects, if any, occur more slowly.
Duration of Action	Duration of action for Vagifem is 24 hours after each dose, but given the local delivery, clinical effects persist with regular use. Symptoms may recur within a few days to weeks after discontinuation.

Classification & Brands

Dosing & administration

One vaginal tablet (10 mcg estradiol) inserted daily for 2 weeks, then maintenance of one tablet twice weekly.

Dosage form	TABLET
Renal impairment	No dose adjustment required for renal impairment.
Liver impairment	Contraindicated in severe hepatic disease (Child-Pugh class C). Use with caution in mild to moderate impairment (Child-Pugh A or B) with monitoring; specific dose reductions not defined.
Pediatric use	Not indicated for use in pediatric patients (safety and efficacy not established).
Geriatric use	Use lowest effective dose; monitor for endometrial hyperplasia/bleeding and thromboembolic risk. No specific dose reduction required.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for VAGIFEM (VAGIFEM).

Breastfeeding	Estradiol is excreted in breast milk in small amounts. M/P ratio not established. Potential for reduced milk production and adverse effects in nursing infant; use with caution only if clearly needed.
Teratogenic Risk	Pregnancy Category X. First trimester: Increased risk of genital tract abnormalities in female offspring (e.g., vaginal adenosis, cervical erosion, clear cell adenocarcinoma). Second and third trimesters: Possible increased risk of urogenital anomalies and later reproductive dysfunction; use is contraindicated throughout pregnancy.

Warnings & precautions

■ FDA Black Box Warning

Estrogen-alone therapy increases the risk of endometrial cancer. Estrogen plus progestin therapy increases the risk of breast cancer, stroke, and deep vein thrombosis.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Undiagnosed abnormal genital bleeding","Known, suspected, or history of breast cancer","Known or suspected estrogen-dependent neoplasia","Active or history of venous thromboembolism (e.g., DVT, PE)","Active or history of arterial thromboembolism (e.g., stroke, MI)","Hepatic impairment or disease","Known hypersensitivity to estradiol or any ingredient","Pregnancy"]

Clinical Precautions

Precautions

["Cardiovascular disorders: Increased risk of stroke and DVT","Malignant neoplasms: Endometrial cancer, breast cancer","Gallbladder disease","Hypercalcemia in patients with bone metastases","Hereditary angioedema","Visual abnormalities (e.g., retinal vascular thrombosis)","Exacerbation of endometriosis"]

Clinical Tips & Counseling

Drug interactions

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VAGIFEM

Clinical safety rating: caution

Comprehensive clinical and safety monograph for VAGIFEM (VAGIFEM).

How it works

What the body does with it

Metabolism	Primarily hepatic via CYP3A4. Undergoes extensive first-pass metabolism when administered orally; however, vaginal administration reduces first-pass effect.
Excretion	Vagifem (estradiol) undergoes hepatic metabolism and renal excretion. Approximately 60-80% of a dose is excreted in urine as glucuronide and sulfate conjugates, with about 10-15% excreted in feces via biliary elimination. Unchanged estradiol is minimally excreted.
Half-life	The terminal elimination half-life of estradiol is approximately 2-3 hours. Due to enterohepatic recirculation, the effective half-life may be longer, and daily dosing maintains steady-state concentrations.
Protein binding	Estradiol is approximately 98% bound to sex hormone-binding globulin (SHBG) and albumin, with SHBG binding being of higher affinity.
Volume of Distribution	The volume of distribution for estradiol is approximately 1 L/kg (range 0.5-1.5 L/kg), indicating extensive distribution into tissues, particularly fat and reproductive organs.
Bioavailability	Vagifem has a bioavailability of approximately 5-10% via vaginal route due to first-pass hepatic metabolism. Oral bioavailability is less than 5%, but not relevant for this product.
Onset of Action	The onset of action for Vagifem (estradiol vaginal tablet) is 2-4 weeks for improvement in vaginal symptoms (e.g., dryness, dyspareunia). Systemic effects, if any, occur more slowly.
Duration of Action	Duration of action for Vagifem is 24 hours after each dose, but given the local delivery, clinical effects persist with regular use. Symptoms may recur within a few days to weeks after discontinuation.

Classification & Brands

Dosing & administration

One vaginal tablet (10 mcg estradiol) inserted daily for 2 weeks, then maintenance of one tablet twice weekly.

Dosage form	TABLET
Renal impairment	No dose adjustment required for renal impairment.
Liver impairment	Contraindicated in severe hepatic disease (Child-Pugh class C). Use with caution in mild to moderate impairment (Child-Pugh A or B) with monitoring; specific dose reductions not defined.
Pediatric use	Not indicated for use in pediatric patients (safety and efficacy not established).
Geriatric use	Use lowest effective dose; monitor for endometrial hyperplasia/bleeding and thromboembolic risk. No specific dose reduction required.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for VAGIFEM (VAGIFEM).

Breastfeeding	Estradiol is excreted in breast milk in small amounts. M/P ratio not established. Potential for reduced milk production and adverse effects in nursing infant; use with caution only if clearly needed.
Teratogenic Risk	Pregnancy Category X. First trimester: Increased risk of genital tract abnormalities in female offspring (e.g., vaginal adenosis, cervical erosion, clear cell adenocarcinoma). Second and third trimesters: Possible increased risk of urogenital anomalies and later reproductive dysfunction; use is contraindicated throughout pregnancy.

Warnings & precautions

■ FDA Black Box Warning

Estrogen-alone therapy increases the risk of endometrial cancer. Estrogen plus progestin therapy increases the risk of breast cancer, stroke, and deep vein thrombosis.