DELATESTRYL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DELATESTRYL (DELATESTRYL).
Testosterone ester; binds to androgen receptors, activating gene transcription and promoting protein synthesis, muscle growth, and secondary sexual characteristics.
| Metabolism | Primarily hepatic via CYP3A4 and other cytochrome P450 enzymes; undergoes ester hydrolysis to testosterone, then further metabolized to androstenedione, dihydrotestosterone, and glucuronide conjugates. |
| Excretion | Urinary (90% as glucuronide and sulfate conjugates, 5% as unchanged drug); fecal (5%) |
| Half-life | 8 days (terminal); requires 5-6 weeks to reach steady state with weekly dosing |
| Protein binding | 97-99% bound to sex hormone-binding globulin (SHBG) and albumin |
| Volume of Distribution | 0.5-0.8 L/kg; large distribution into muscle and adipose tissue, with slow release from injection site |
| Bioavailability | Intramuscular: 100% (complete absorption from oily depot); oral: <5% due to extensive first-pass metabolism |
| Onset of Action | Intramuscular: 24-48 hours for clinical effect; peak plasma levels at 24-72 hours |
| Duration of Action | Intramuscular: 2-4 weeks (clinical duration); residual effects may persist up to 6 weeks after discontinuation |
50 to 200 mg intramuscularly every 2 to 4 weeks.
| Dosage form | INJECTABLE |
| Renal impairment | No adjustment required; not significantly renally eliminated. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C); use with caution in mild to moderate impairment. |
| Pediatric use | 50 mg intramuscularly every 4 weeks for delayed puberty; adjust based on response. |
| Geriatric use | Use lowest effective dose; monitor for prostate enlargement, fluid retention, and cardiovascular effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DELATESTRYL (DELATESTRYL).
| Breastfeeding | Contraindicated during breastfeeding. Excreted into human milk; M/P ratio unknown. Potential for adverse effects on infant including virilization and disruption of growth. |
| Teratogenic Risk | FDA Pregnancy Category X. Contraindicated in pregnancy. Androgens can cause virilization of female fetus (clitoromegaly, labial fusion, urogenital sinus abnormality) when administered during the first trimester; during second and third trimesters, can cause ambiguous genitalia in female fetuses and precocious sexual development in male fetuses. |
■ FDA Black Box Warning
Virilization has been reported in children; use with caution in patients with conditions susceptible to edema; prolonged use may cause azoospermia.
| Serious Effects |
Men with breast cancer or known/suspected prostate cancer; pregnancy (androgenic effects on fetus); hypersensitivity to any component.
| Precautions | Monitor for polycythemia, sleep apnea, and prostatic hyperplasia; may increase risk of cardiovascular events; use with caution in patients with renal, hepatic, or cardiac disease. |
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| Fetal Monitoring |
| Monitor maternal signs of virilization (hirsutism, acne, voice deepening); fetal ultrasound for sexual development if inadvertent exposure; maternal liver function tests, lipid profile, and hematocrit due to increased erythropoiesis risk. |
| Fertility Effects | Can impair spermatogenesis in males (oligospermia, decreased sperm motility) and may cause ovulation suppression or menstrual irregularities in females. Reversible upon discontinuation. |