TESTODERM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TESTODERM (TESTODERM).
Testosterone replacement therapy: binds to androgen receptors, activating gene transcription for protein synthesis and muscle growth.
| Metabolism | Hepatic via reduction and conjugation; metabolites include androstenedione, dihydrotestosterone, and various glucuronides and sulfates. |
| Excretion | Primarily renal (approximately 90% as glucuronide and sulfate conjugates, <10% as unchanged testosterone); about 6% is excreted in feces via biliary elimination. |
| Half-life | Terminal elimination half-life is approximately 10-100 minutes for free testosterone in plasma; for total testosterone (including bound), the apparent half-life ranges from 2-4 hours after transdermal application, with significant interindividual variability. |
| Protein binding | Approximately 97-99% bound, primarily to sex hormone-binding globulin (SHBG, about 40%) and albumin (about 58%); only 1-3% is free. |
| Volume of Distribution | Apparent volume of distribution is approximately 1.0 L/kg (range 0.5-1.5 L/kg), reflecting extensive tissue binding and distribution into target organs such as muscle, prostate, and adipose tissue. |
| Bioavailability | Transdermal: Approximately 10-20% of the applied dose is absorbed systemically across intact skin; absolute bioavailability depends on formulation and application site, with scrotal skin providing higher absorption than nonscrotal skin. |
| Onset of Action | Transdermal: Serum testosterone levels begin to increase within 2-4 hours after application; physiological levels are typically achieved within 4-8 hours. |
| Duration of Action | Transdermal: Serum testosterone levels remain elevated for 24 hours after single application; continuous daily application maintains steady-state concentrations within the normal male range. |
| Molecular Weight | 288.42 |
One to two 2.5 mg or 5 mg patches applied to clean, dry, intact skin of the back, abdomen, upper arms, or thighs once daily (approximately every 24 hours).
| Dosage form | FILM, EXTENDED RELEASE |
| Renal impairment | No dose adjustment required for renal impairment. However, testosterone replacement may unmask or worsen fluid retention; use with caution in severe renal impairment. |
| Liver impairment | Contraindicated in patients with severe hepatic impairment (Child-Pugh class C). For mild to moderate impairment (Child-Pugh A or B), use with caution; no specific dose adjustment guidelines exist. |
| Pediatric use | Testosterone patch (Testoderm) is not indicated for use in pediatric patients; safety and efficacy have not been established. |
| Geriatric use | Elderly patients may have increased risk of prostatic hyperplasia and prostatic carcinoma; monitor prostate-specific antigen (PSA) and digital rectal exam periodically. Start at lower end of dosing range (e.g., 2.5 mg/day) and titrate based on serum testosterone levels and clinical response. |
| 1st trimester | Avoid during pregnancy; testosterone is contraindicated due to virilization of female fetus and potential teratogenicity. |
| 2nd trimester | Avoid; continued risk of fetal harm including virilization and developmental effects. |
| 3rd trimester | Avoid; risk of fetal harm persists, and may affect neonatal outcomes. |
Clinical note
Comprehensive clinical and safety monograph for TESTODERM (TESTODERM).
| Placental transfer | Testosterone readily crosses the placenta; exogenous administration leads to elevated fetal levels and risk of virilization. |
| Breastfeeding | Testosterone is excreted into breast milk in small amounts; however, it may cause virilization in female nursing infants. Long-term effects are unknown. Generally not recommended during breastfeeding unless potential benefits outweigh risks. |
■ FDA Black Box Warning
Testosterone has not been shown to be safe or effective for treating low testosterone levels due to aging alone. Increased risk of cardiovascular events, including myocardial infarction and stroke, has been reported with testosterone use.
| Serious Effects |
Known or suspected prostate cancerKnown or suspected breast cancer in malesHypersensitivity to testosterone or any excipientsPregnancySevere lower urinary tract symptoms related to benign prostatic hyperplasia
| Precautions | Cardiovascular risk: possible increased risk of myocardial infarction and stroke, Polycythemia (elevated hematocrit), Prostatic hyperplasia/prostate cancer risk (increased PSA), Sleep apnea exacerbation, Fluid retention/edema, Virilization in women (pregnancy category X), Hypercalcemia in immobilized patients |
| Food/Dietary | No specific food restrictions other than maintaining a consistent diet as instructed. Grapefruit juice may increase testosterone absorption; avoid excessive intake. Alcohol consumption may alter testosterone metabolism; limit to moderate intake. |
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| Lactation Rating |
| L4 - Possibly Hazardous |
| Teratogenic Risk | Testosterone (Testoderm) is pregnancy category X. Use is contraindicated in pregnant women. Testosterone can cause virilization of the female fetus when administered during the first trimester (organogenesis) and may cause clitoromegaly, labial fusion, and other urogenital anomalies. Exposure during the second and third trimesters can lead to hirsutism, masculinization, and advanced bone age. There is no known risk of structural defects from later exposure, but androgenic effects persist. |
| Fetal Monitoring | Monitor maternal blood pressure, lipid profile, liver function, and signs of virilization (e.g., hirsutism, acne, deepening voice). Fetal monitoring: ultrasound for growth and anatomy if inadvertent exposure occurs. Serum testosterone levels may be monitored to avoid supraphysiologic levels. |
| Fertility Effects | Exogenous testosterone suppresses the hypothalamic-pituitary-gonadal axis, reducing endogenous testosterone production and spermatogenesis. Reversible oligospermia or azoospermia may occur, impairing male fertility. Effects resolve after discontinuation. In females, testosterone may disrupt ovulatory cycles and reduce fertility. |
| Clinical Pearls | Apply to clean, dry, intact skin on abdomen, thighs, upper arms, or back. Avoid scrotum, axillae, or bony prominences. Rotate application sites to minimize skin reactions. Do not apply to genital area or breasts. Wash hands after application. Cover application site with clothing to prevent transfer to others. Monitor serum testosterone levels 4-8 weeks after initiation, target mid-normal range (400-700 ng/dL). Avoid smoking cessation within 24 hours of application (increases absorption). Contraindicated in breast cancer, prostate cancer, and men with azoospermia. |
| Patient Advice | Apply the patch to a different skin site each day to prevent irritation. · Do not apply the patch to the scrotum, axillae, or areas of broken skin. · Wash hands thoroughly after handling the patch. · Keep the application site covered with clothing to avoid transferring testosterone to others, especially children and women. · If the patch falls off, apply a new patch to a different site; do not reuse the old patch. · Contact your doctor if you experience severe skin irritation, persistent erections, or signs of prostate enlargement. · Store patches at room temperature away from moisture and heat. · Do not use the patch if the pouch seal is broken or missing. |