Testosterone

What it is and how it works

Mechanism of Action Endogenous androgens, including testosterone and dihydrotestosterone (DHT), are responsible for the normal growth and development of the male sex organs and for maintenance of secondary sex characteristics. These effects include the growth and maturation of prostate, seminal vesicles, penis and scrotum; the development of male hair distribution, such as facial, pubic, chest and axillary hair; laryngeal enlargement; vocal chord thickening; and alterations in body musculature and fat distribution. Testosterone and DHT are necessary for the normal development of secondary sex characteristics.

Mechanism class: Androgen Receptor Agonists

Indications

Testosterone gel 1.62% is indicated for replacement therapy in adult males for conditions associated with a deficiency or absence of endogenous testosterone: Primary hypogonadism (congenital or acquired): testicular failure due to conditions such as cryptorchidism, bilateral torsion, orchitis, vanishing testis syndrome, orchiectomy, Klinefelter's syndrome, chemotherapy, or toxic damage from alcohol or heavy metals. These men usually have low serum testosterone concentrations and gonadotropins (follicle-stimulating hormone [FSH], luteinizing hormone [LH]) above the normal range. Hypogonadotropic hypogonadism (congenital or acquired): gonadotropin or luteinizing hormone-releasing hormone (LHRH) deficiency or pituitary-hypothalamic injury from tumors, trauma, or radiation. These men have low testosterone serum concentrations, but have gonadotropins in the normal or low range. Limitations of use: Safety and efficacy of testosterone gel 1.62% in men with “age-related hypogonadism” (also referred to as “late-onset hypogonadism”) have not been established.

Dosage and administration (summary)

Dosage and Administration for testosterone gel 1.62% differs from testosterone gel 1%. For dosage and administration of testosterone gel 1% refer to its full prescribing information. Prior to initiating testosterone gel 1.62%, confirm the diagnosis of hypogonadism by ensuring that serum testosterone concentrations have been measured in the morning on at least two separate days and that these serum testosterone concentrations are below the normal range. Dosage and Administration for testosterone gel 1.62% differs from testosterone gel 1%. For dosage and administration of testosterone gel 1% refer to its full prescribing information.

Contraindications

Testosterone gel 1.62% is contraindicated in men with carcinoma of the breast or known or suspected carcinoma of the prostate . Testosterone gel 1.62% is contraindicated in women who are pregnant. Testosterone gel 1.62% can cause virilization of the female fetus when administered to a pregnant woman. Pregnant women need to be aware of the potential for transfer of testosterone from men treated with testosterone gel 1.62%.

Warnings and precautions

Monitor patients with benign prostatic hyperplasia (BPH) for worsening of signs and symptoms of BPH Avoid unintentional exposure of women or children to testosterone gel 1.62%. Secondary exposure to testosterone can produce signs of virilization. Testosterone gel 1.62% should be discontinued until the cause of virilization is identified Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE) have been reported in patients using testosterone products. Evaluate patients with signs or symptoms consistent with DVT or PE.

Pregnancy

Pregnancy Risk Summary Testosterone gel 1.62% is contraindicated in pregnant women. Testosterone is teratogenic and may cause fetal harm when administered to a pregnant woman based on data from animal studies and its mechanism of action . Exposure of a female fetus to androgens may result in varying degrees of virilization.

Storage and supply

Testosterone gel 1.62% is supplied in non-aerosol, metered-dose pumps that deliver 20.25 mg of testosterone per complete pump actuation. The pumps are composed of plastic and stainless steel and an LDPE/aluminum foil inner liner encased in rigid plastic with a polypropylene cap.

Source: Testosterone (Testosterone) — US FDA prescribing information, 2024-09-30, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.