TESTODERM TTS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TESTODERM TTS (TESTODERM TTS).
Testosterone is an androgen receptor agonist. It binds to and activates androgen receptors, leading to changes in gene expression that promote the development and maintenance of male secondary sexual characteristics, anabolic effects, and spermatogenesis.
| Metabolism | Testosterone is metabolized primarily in the liver via reduction and conjugation, with CYP3A4 isoenzyme involvement. Also metabolized to dihydrotestosterone (DHT) by 5α-reductase and to estradiol by aromatase. |
| Excretion | Testosterone is excreted primarily in the urine as glucuronide and sulfate conjugates (approximately 90%), with about 6% excreted in feces via bile. Less than 1% is excreted unchanged. |
| Half-life | The terminal elimination half-life of testosterone administered transdermally is approximately 1.5–2 hours. This short half-life requires daily application of the patch to maintain therapeutic levels. |
| Protein binding | Testosterone is extensively bound to plasma proteins: approximately 97–99% bound, primarily to sex hormone-binding globulin (SHBG, about 40%) and albumin (about 60%). Only 1–3% is free (unbound) and biologically active. |
| Volume of Distribution | The apparent volume of distribution (Vd) of testosterone is approximately 1.0 L/kg, indicating distribution into total body water and extensive tissue binding, particularly to muscle, skin, and prostate. |
| Bioavailability | Transdermal bioavailability of testosterone from Testoderm TTS is approximately 15–25% of the applied dose, due to incomplete absorption and first-pass cutaneous metabolism. The patch delivers 2.5–5 mg of testosterone per day depending on patch size. |
| Onset of Action | Following transdermal application of Testoderm TTS, serum testosterone concentrations reach therapeutic levels within 2–4 hours, with steady-state achieved after 2–3 days of daily dosing. |
| Duration of Action | The duration of action is approximately 24 hours, requiring once-daily application. Serum testosterone levels remain within the normal range for the dosing interval, but decline to baseline within 24 hours after patch removal. |
| Molecular Weight | 288.42 |
Apply 4 mg (one 4 mg/24 hr system) or 6 mg (one 6 mg/24 hr system) transdermally once daily, applied to clean, dry, intact skin on the back, abdomen, thighs, or upper arms. Rotate application sites with an interval of at least 7 days.
| Dosage form | FILM, EXTENDED RELEASE |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment. Use with caution in severe renal impairment (GFR <30 mL/min) due to potential for accumulation of excipients; monitor testosterone levels. |
| 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 and monitor liver function and testosterone levels; no specific dose modification established. |
| Pediatric use | Not indicated for use in pediatric patients (safety and efficacy not established). Androgen replacement therapy is typically initiated only in adolescent males with confirmed hypogonadism under specialist supervision; weight-based dosing not recommended. |
| Geriatric use | Use with caution in elderly patients due to increased risk of prostatic hyperplasia and prostatic carcinoma. Monitor prostate-specific antigen (PSA) and hematocrit. Initiate at lowest effective dose (e.g., 4 mg/day) and titrate based on serum testosterone levels. |
| 1st trimester | Contraindicated. Testosterone can cause virilization of female fetus. |
| 2nd trimester | Contraindicated. Androgens may cause virilization and clitoral enlargement. |
| 3rd trimester | Contraindicated. Potential for fetal harm, including ambiguous genitalia. |
Clinical note
Comprehensive clinical and safety monograph for TESTODERM TTS (TESTODERM TTS).
| Placental transfer | Testosterone crosses the placenta and can cause virilization of female fetuses. |
| Breastfeeding | Testosterone is excreted in breast milk. Use is not recommended due to potential adverse effects on infant development, including virilization and growth disturbances. |
| Lactation Rating |
■ FDA Black Box Warning
WARNING: SECONDARY EXPOSURE TO TESTOSTERONE. Testosterone can be transferred to others through direct skin contact, leading to adverse effects in children and women. Patients should wash hands after application, cover application site with clothing, and wash skin before direct contact with others.
| Serious Effects |
Known or suspected prostate cancerKnown or suspected breast cancer in malesHypersensitivity to testosterone or any components of the patch
| Precautions | Secondary exposure risk and virilization in children and women, Polycythemia - increased risk of cardiovascular events, Prostate cancer and benign prostatic hyperplasia (BPH) exacerbation, Hepatic adverse effects including cholestatic hepatitis and jaundice, Edema in patients with preexisting cardiac, renal, or hepatic disease, Lipid profile changes (decreased HDL) |
| Food/Dietary | No specific food interactions reported. Maintain a normal diet. Avoid excessive alcohol consumption as it may affect testosterone levels. |
Loading safety data…
| L5 - Contraindicated |
| Teratogenic Risk | Testosterone is contraindicated in pregnancy. Exposure during the first trimester is associated with virilization of the female fetus, including clitoromegaly and labial fusion. Second and third trimester exposure may cause pseudohermaphroditism in female fetuses. Androgens can cross the placenta and disrupt normal sexual differentiation. |
| Fetal Monitoring | Monitoring includes maternal serum testosterone levels (target within physiological range for pregnancy if used for specific conditions), fetal ultrasound for signs of virilization (ambiguous genitalia), and assessment of maternal adverse effects such as hirsutism, acne, and voice changes. |
| Fertility Effects | Testosterone suppresses endogenous gonadotropin secretion, which can impair spermatogenesis in males. In females, supraphysiological doses may disrupt menstrual cycles and reduce fertility. These effects are generally reversible upon discontinuation. |
| Clinical Pearls | Testoderm TTS is a testosterone transdermal system indicated for testosterone replacement therapy in males with hypogonadism. Apply to clean, dry, non-scrotal skin on the back, abdomen, upper arms, or thighs. Avoid application over bony prominences. Rotate application sites to minimize skin irritation. Monitor serum testosterone levels 2-4 hours after application during the first month of therapy. Do not use in women or children. Beware of potential for secondary exposure to women and children through direct skin contact. |
| Patient Advice | Apply the patch to clean, dry skin on the back, abdomen, upper arm, or thigh, but not on the scrotum. · Rotate application sites to avoid skin irritation; do not apply to the same site within 7 days. · Do not cut or damage the patch; apply immediately after opening. · Wash hands after handling the patch and avoid direct skin contact with women or children. · Do not smoke or apply near heat sources (e.g., heating pads, electric blankets) as increased absorption may occur. · Report signs of excessive testosterone levels (e.g., acne, fluid retention, aggressive behavior) or skin reactions. · Regular blood tests are required to monitor testosterone levels and prostate health. |