TESTOSTERONE ENANTHATE AND ESTRADIOL VALERATE
Clinical safety rating: avoid
Corticosteroids may increase edema risk and anticoagulants may have increased effects Can cause polycythemia and increased risk of cardiovascular events.
Testosterone enanthate is a prodrug of testosterone, which binds to androgen receptors, activating gene transcription that leads to development of male secondary sex characteristics and anabolic effects. Estradiol valerate is a prodrug of estradiol, which binds to estrogen receptors, promoting growth and development of female reproductive tissues and secondary sex characteristics.
| Metabolism | Testosterone enanthate is hydrolyzed to testosterone, which is metabolized by CYP3A4 and other CYP enzymes to active metabolites (estradiol and dihydrotestosterone). Estradiol valerate is hydrolyzed to estradiol, which is metabolized by CYP3A4 and other CYP enzymes to estrone and estriol. Both undergo glucuronidation and sulfation. |
| Excretion | Testosterone enanthate and estradiol valerate are metabolized in the liver. Testosterone metabolites (e.g., androsterone, etiocholanolone) are conjugated and excreted renally (90%) and fecally (~10%). Estradiol valerate is hydrolyzed to estradiol, metabolized to estrone and estriol, conjugated, and excreted primarily renally (70-80%) with ~20% biliary/fecal. |
| Half-life | Testosterone enanthate: 4-5 days (IM). Estradiol valerate: 2-3 days (IM). Steady-state reached in ~2-3 weeks. |
| Protein binding | Testosterone: 98% bound to sex hormone-binding globulin (SHBG) and albumin. Estradiol: 98% bound to SHBG and albumin. |
| Volume of Distribution | Testosterone enanthate: Vd ~1.0 L/kg; estradiol valerate: Vd ~1.2 L/kg. High Vd indicates extensive tissue distribution. |
| Bioavailability | IM injection: ~100% bioavailability due to depot effect; oral bioavailability negligible (<5%) due to first-pass metabolism; not available as transdermal for this combination. |
| Onset of Action | IM injection: Testosterone effects (muscle growth, libido) within 1-3 days; estradiol effects (feminization, breast tenderness) within 2-5 days. |
| Duration of Action | Testosterone enanthate: 2-4 weeks; estradiol valerate: 1-2 weeks. Dosing interval typically 2-4 weeks. |
1 to 2 mL of a combination product containing 90 mg testosterone enanthate and 4 mg estradiol valerate per mL intramuscularly every 4 weeks.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment recommended; use with caution in severe renal impairment due to potential fluid retention. |
| Liver impairment | Contraindicated in patients with severe hepatic impairment (Child-Pugh class C). In mild to moderate impairment (Child-Pugh A or B), monitor liver function and adjust dose based on clinical response and tolerability; specific dosing guidelines not established. |
| Pediatric use | Not indicated for use in pediatric patients; safety and efficacy not established. |
| Geriatric use | Use with caution in elderly patients due to increased risk of prostate hypertrophy, cardiovascular events, and fluid retention. Initiate at lower end of dosing range and monitor closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Corticosteroids may increase edema risk and anticoagulants may have increased effects Can cause polycythemia and increased risk of cardiovascular events.
| FDA category | Contraindicated |
| Breastfeeding | Contraindicated during breastfeeding. Testosterone passes into breast milk and may suppress lactation; estradiol valerate is excreted in small amounts. M/P ratio not established. |
| Teratogenic Risk | First trimester: Androgen exposure may cause virilization of female fetus (clitoromegaly, labial fusion). Estradiol valerate may increase risk of congenital anomalies including cardiovascular and neural tube defects. Second and third trimesters: Continued virilization risk; estradiol may cause feminization in male fetuses and potential long-term reproductive effects. |
■ FDA Black Box Warning
Estrogen-progestin combinations (including estradiol valerate) increase the risk of cardiovascular events, thromboembolism, and breast cancer. Testosterone has been associated with increased risk of cardiovascular events and prostate cancer.
| Common Effects | Acne |
| Serious Effects |
Known or suspected pregnancy (estradiol), breastfeeding, undiagnosed abnormal genital bleeding, known or suspected breast cancer (estradiol), active thromboembolic disease, known or suspected prostate cancer (testosterone), severe hepatic disease.
| Precautions | Monitor for thromboembolic events, cardiovascular disease, and lipid changes. Use with caution in patients with hepatic impairment, renal disease, or a history of myocardial infarction. May cause fluid retention, hypertension, and hypoglycemia in diabetics. Testosterone may accelerate growth of androgen-dependent tumors. Estradiol may increase risk of endometrial cancer. |
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| Fetal Monitoring | Monitor maternal blood pressure, liver function, lipid profile, blood glucose, and signs of thromboembolism. Fetal ultrasound for growth and anatomy if exposure occurs. Consider amniocentesis if virilization suspected. |
| Fertility Effects | Testosterone enanthate suppresses gonadotropins, impairing spermatogenesis and ovulation; may cause reversible infertility. Estradiol valerate may disrupt menstrual cycle and ovulation. Long-term use may reduce fertility. |