FORTESTA

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FORTESTA (FORTESTA).

How it works

Testosterone replacement therapy; testosterone binds to and activates androgen receptors, influencing gene transcription and protein synthesis, leading to the development of male secondary sex characteristics and maintenance of libido, muscle mass, and bone density.

What the body does with it

Metabolism	Metabolized primarily in the liver via reduction and conjugation; major metabolites include androsterone and etiocholanolone; also undergoes some extrahepatic metabolism in skin.
Excretion	Primarily renal (90% as glucuronide and sulfate conjugates, 10% unchanged); approximately 1% fecal.
Half-life	Terminal elimination half-life is 3–4 hours; not clinically significant for once-daily transdermal administration due to sustained absorption.
Protein binding	Testosterone is 97–99% bound to sex hormone-binding globulin (SHBG) and albumin.
Volume of Distribution	Approximately 0.5–1.0 L/kg, indicating distribution into total body water and extensive tissue binding.
Bioavailability	Transdermal: Approximately 10% of applied dose reaches systemic circulation; exact absorption varies with application site and skin condition.
Onset of Action	Transdermal: Clinical effects (testosterone normalization) observed within 24 hours of first application.
Duration of Action	Transdermal: Approximately 24 hours with once-daily application; maintains steady-state testosterone levels within normal range.

Classification & Brands

Action Class	Antiprotozoal agents
Brand Substitutes	Neomex 500mg Tablet, Mebendex 500mg Tablet, Mebex 500mg Tablet

Dosing & administration

Apply one 30 mg metered-dose transdermal system to abdomen or upper arm once daily at the same time each day.

Dosage form	GEL, METERED
Renal impairment	No specific dose adjustment recommended; use with caution in severe renal impairment (CrCl <30 mL/min).
Liver impairment	No specific dose adjustment recommended for Child-Pugh A or B; avoid in Child-Pugh C due to lack of data.
Pediatric use	Not approved for use in pediatric patients.
Geriatric use	Limited data in patients >75 years; use lowest effective dose and monitor for adverse effects.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for FORTESTA (FORTESTA).

Breastfeeding	Testosterone is excreted in breast milk. M/P ratio not established. Potential for virilization of infant. Breastfeeding not recommended during therapy. Discontinue drug or nursing.
Teratogenic Risk	FORTESTA (testosterone) is contraindicated in pregnancy due to masculinization of female fetus. Second and third trimester exposure may cause clitoromegaly, labial fusion, and other virilization. First trimester risk is theoretical but avoided.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

WARNING: SECONDARY EXPOSURE TO TESTOSTERONE - Cases of secondary exposure to testosterone in children and women have been reported, including cases of virilization. Advise patients to strictly adhere to recommended use and apply to clean, dry skin; wash hands after application; cover application site with clothing; and wash site prior to skin-to-skin contact with others.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Men with carcinoma of the breast or known or suspected carcinoma of the prostate","Pregnant or breastfeeding women (testosterone may cause fetal harm)","Hypersensitivity to testosterone or any component of the formulation","History of myocardial infarction or stroke within the past 6 months"]

Clinical Precautions

Precautions

["Secondary exposure to testosterone (children and women)","Worsening of benign prostatic hyperplasia (BPH)","Increased risk of prostate cancer","Cardiovascular risk (including myocardial infarction and stroke) in patients with pre-existing risk factors","Hepatic effects: cholestatic jaundice, liver tumors","Edema with or without congestive heart failure","Polycythemia (increased hematocrit)","Sleep apnea in susceptible individuals","Gynecomastia","Hypercalcemia in immobilized patients or those with metastatic breast cancer"]

Clinical Tips & Counseling

Drug interactions

Loading safety data…

FORTESTA

Clinical safety rating: caution

Comprehensive clinical and safety monograph for FORTESTA (FORTESTA).

How it works

What the body does with it

Metabolism	Metabolized primarily in the liver via reduction and conjugation; major metabolites include androsterone and etiocholanolone; also undergoes some extrahepatic metabolism in skin.
Excretion	Primarily renal (90% as glucuronide and sulfate conjugates, 10% unchanged); approximately 1% fecal.
Half-life	Terminal elimination half-life is 3–4 hours; not clinically significant for once-daily transdermal administration due to sustained absorption.
Protein binding	Testosterone is 97–99% bound to sex hormone-binding globulin (SHBG) and albumin.
Volume of Distribution	Approximately 0.5–1.0 L/kg, indicating distribution into total body water and extensive tissue binding.
Bioavailability	Transdermal: Approximately 10% of applied dose reaches systemic circulation; exact absorption varies with application site and skin condition.
Onset of Action	Transdermal: Clinical effects (testosterone normalization) observed within 24 hours of first application.
Duration of Action	Transdermal: Approximately 24 hours with once-daily application; maintains steady-state testosterone levels within normal range.

Classification & Brands

Action Class	Antiprotozoal agents
Brand Substitutes	Neomex 500mg Tablet, Mebendex 500mg Tablet, Mebex 500mg Tablet

Dosing & administration

Apply one 30 mg metered-dose transdermal system to abdomen or upper arm once daily at the same time each day.

Dosage form	GEL, METERED
Renal impairment	No specific dose adjustment recommended; use with caution in severe renal impairment (CrCl <30 mL/min).
Liver impairment	No specific dose adjustment recommended for Child-Pugh A or B; avoid in Child-Pugh C due to lack of data.
Pediatric use	Not approved for use in pediatric patients.
Geriatric use	Limited data in patients >75 years; use lowest effective dose and monitor for adverse effects.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for FORTESTA (FORTESTA).

Breastfeeding	Testosterone is excreted in breast milk. M/P ratio not established. Potential for virilization of infant. Breastfeeding not recommended during therapy. Discontinue drug or nursing.
Teratogenic Risk	FORTESTA (testosterone) is contraindicated in pregnancy due to masculinization of female fetus. Second and third trimester exposure may cause clitoromegaly, labial fusion, and other virilization. First trimester risk is theoretical but avoided.
Fetal Monitoring