ORETON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ORETON (ORETON).
Androgen receptor agonist; binds to androgen receptors, stimulating protein synthesis, growth of male reproductive tissues, and development of secondary sexual characteristics.
| Metabolism | Hepatic via CYP3A4 and 17β-hydroxysteroid dehydrogenase; undergoes extensive first-pass metabolism; metabolites include androsterone and etiocholanolone conjugated as glucuronides and sulfates. |
| Excretion | Renal (90% as metabolites, 5% unchanged), biliary/fecal (10%) |
| Half-life | 8 hours for testosterone; clinical context: requires daily or weekly dosing for replacement therapy |
| Protein binding | 98% bound to sex hormone-binding globulin and albumin |
| Volume of Distribution | 0.5-1.0 L/kg, indicating extensive tissue distribution |
| Bioavailability | Intramuscular: 100%; Oral: <5% due to first-pass metabolism; Transdermal: 10-20% |
| Onset of Action | Intramuscular: 1-2 days; Subcutaneous: 2-4 hours; Transdermal: 2-4 hours |
| Duration of Action | Intramuscular: 2-4 weeks; Subcutaneous: 2-4 weeks; Transdermal: 24 hours |
Testosterone enanthate 50-400 mg IM every 2-4 weeks.
| Dosage form | TABLET |
| Renal impairment | No adjustment required for mild to moderate impairment; use with caution in severe impairment (CrCl <30 mL/min) due to potential edema. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C); use with caution in moderate impairment (Child-Pugh class B) with reduced initial doses. |
| Pediatric use | Not indicated for use in children; safety and efficacy not established. |
| Geriatric use | Start with lower doses (e.g., 50-100 mg IM every 2-4 weeks) due to increased risk of prostate hyperplasia and cardiovascular events. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ORETON (ORETON).
| Breastfeeding | Testosterone is excreted into breast milk. M/P ratio unknown. May cause virilization in nursing infants. Contraindicated during breastfeeding. |
| Teratogenic Risk | ORETON (testosterone propionate) is contraindicated in pregnancy due to virilization of female fetus. First trimester: highest risk of clitoromegaly, labial fusion. Second/third trimesters: risk of clitoromegaly, urogenital sinus abnormalities. No safe use. |
| Fetal Monitoring |
■ FDA Black Box Warning
Prolonged use of high doses of androgens has been associated with development of hepatic adenomas, hepatocellular carcinoma, and peliosis hepatis. Androgens are contraindicated in men with known or suspected prostate or breast cancer.
| Serious Effects |
["Known or suspected prostate or breast cancer in males","Hypersensitivity to any component","Severe hepatic or renal impairment","Pregnancy and breastfeeding","Women with hypercalcemia (due to increased risk of hypercalcemia)"]
| Precautions | ["Monitor liver function due to risk of hepatotoxicity","Monitor serum cholesterol and lipid profile","May cause fluid retention and edema","Use with caution in patients with renal, hepatic, or cardiac disease","Prolonged use may accelerate bone maturation in children","Androgenic effects may cause virilization in women"] |
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| If accidental exposure during pregnancy, monitor fetal growth and anatomy via ultrasound. Monitor infant for signs of virilization postpartum. No routine monitoring required for mother. |
| Fertility Effects | Testosterone suppresses endogenous gonadotropins, causing oligo/azoospermia and decreased fertility in males. In females, may suppress ovulation. Effects typically reversible upon discontinuation. |