OGEN 5

Clinical safety rating: caution

Comprehensive clinical and safety monograph for OGEN 5 (OGEN 5).

How it works

Estrogen replacement; binds to estrogen receptors, activating gene transcription for estrogenic effects in target tissues.

What the body does with it

Metabolism	Primarily hepatic metabolism via CYP3A4 and other CYP enzymes; undergoes enterohepatic recirculation.
Excretion	Renal (primarily as conjugated metabolites); approximately 50-80% of an oral dose is excreted in urine, with about 20% in feces via biliary elimination.
Half-life	Terminal elimination half-life of estrone (primary active metabolite) is approximately 20 hours; steady-state concentrations achieved within 6-8 days. Half-life of estradiol is shorter (1-2 hours) but clinically the estrogenic effect correlates with estrone.
Protein binding	Estrone and estradiol: approximately 98% bound to sex hormone-binding globulin (SHBG) and albumin.
Volume of Distribution	Volume of distribution for estrogens: approximately 20 L/kg; indicates extensive distribution into tissues, including fat and reproductive organs.
Bioavailability	Oral estrone sulfate: approximately 30-50% due to first-pass metabolism in the liver and gut; interindividual variability due to differences in hydrolysis and conjugation.
Onset of Action	Oral administration: clinical effects (e.g., relief of menopausal symptoms) observed within 1-2 days; full estrogenic effect develops over 1-2 weeks.
Duration of Action	Duration of action after single oral dose: estrogenic effects persist for 12-24 hours; for chronic therapy, continuous dosing maintains effect as long as treatment is continued.

Classification & Brands

Dosing & administration

0.625 mg orally once daily, adjusted based on response.

Dosage form	TABLET
Renal impairment	No dose adjustment required for mild-to-moderate renal impairment; contraindicated in severe renal impairment.
Liver impairment	No specific guidelines; caution in severe hepatic disease.
Pediatric use	Not approved for use in pediatric patients.
Geriatric use	Use lowest effective dose; monitor for thromboembolic events and malignancy.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for OGEN 5 (OGEN 5).

Breastfeeding	Estrogens are excreted in breast milk; M/P ratio not specified. May reduce milk quantity and quality. Not recommended during breastfeeding.
Teratogenic Risk	Estrogen use during pregnancy is contraindicated. First trimester exposure associated with vaginal adenosis and clear cell adenocarcinoma in female offspring; second and third trimester use may cause urogenital anomalies and feminization of male fetuses. Risk of fetal harm is established.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Estrogens increase the risk of endometrial cancer in women with an intact uterus. Unopposed estrogen use is associated with an increased risk of endometrial hyperplasia and carcinoma. Cardiovascular disorders, breast cancer, and probable dementia have also been reported with estrogen therapy.

Side Effect Profile

Serious Effects

Absolute Contraindications

Undiagnosed abnormal genital bleeding, known or suspected breast cancer (except in appropriately selected patients being treated for metastatic disease), known or suspected estrogen-dependent neoplasia, active or past history of venous thromboembolism, active or past history of arterial thromboembolism, known or suspected pregnancy, known liver dysfunction or disease, and known hypersensitivity to any component of the product.

Clinical Precautions

Precautions

Cardiovascular disorders (e.g., stroke, DVT, pulmonary embolism), probable dementia (increased risk in women aged 65 years or older), breast cancer, endometrial cancer, gallbladder disease, hypercalcemia, visual abnormalities, and exacerbation of endometriosis.

Clinical Tips & Counseling

Drug interactions

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OGEN 5

Clinical safety rating: caution

Comprehensive clinical and safety monograph for OGEN 5 (OGEN 5).

How it works

Estrogen replacement; binds to estrogen receptors, activating gene transcription for estrogenic effects in target tissues.

What the body does with it

Metabolism	Primarily hepatic metabolism via CYP3A4 and other CYP enzymes; undergoes enterohepatic recirculation.
Excretion	Renal (primarily as conjugated metabolites); approximately 50-80% of an oral dose is excreted in urine, with about 20% in feces via biliary elimination.
Half-life	Terminal elimination half-life of estrone (primary active metabolite) is approximately 20 hours; steady-state concentrations achieved within 6-8 days. Half-life of estradiol is shorter (1-2 hours) but clinically the estrogenic effect correlates with estrone.
Protein binding	Estrone and estradiol: approximately 98% bound to sex hormone-binding globulin (SHBG) and albumin.
Volume of Distribution	Volume of distribution for estrogens: approximately 20 L/kg; indicates extensive distribution into tissues, including fat and reproductive organs.
Bioavailability	Oral estrone sulfate: approximately 30-50% due to first-pass metabolism in the liver and gut; interindividual variability due to differences in hydrolysis and conjugation.
Onset of Action	Oral administration: clinical effects (e.g., relief of menopausal symptoms) observed within 1-2 days; full estrogenic effect develops over 1-2 weeks.
Duration of Action	Duration of action after single oral dose: estrogenic effects persist for 12-24 hours; for chronic therapy, continuous dosing maintains effect as long as treatment is continued.

Classification & Brands

Dosing & administration

0.625 mg orally once daily, adjusted based on response.

Dosage form	TABLET
Renal impairment	No dose adjustment required for mild-to-moderate renal impairment; contraindicated in severe renal impairment.
Liver impairment	No specific guidelines; caution in severe hepatic disease.
Pediatric use	Not approved for use in pediatric patients.
Geriatric use	Use lowest effective dose; monitor for thromboembolic events and malignancy.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for OGEN 5 (OGEN 5).

Breastfeeding	Estrogens are excreted in breast milk; M/P ratio not specified. May reduce milk quantity and quality. Not recommended during breastfeeding.
Teratogenic Risk	Estrogen use during pregnancy is contraindicated. First trimester exposure associated with vaginal adenosis and clear cell adenocarcinoma in female offspring; second and third trimester use may cause urogenital anomalies and feminization of male fetuses. Risk of fetal harm is established.
Fetal Monitoring