TESTOSTERONE CYPIONATE
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 cypionate is a synthetic androgen that binds to and activates androgen receptors, leading to increased protein synthesis, muscle growth, and secondary sexual characteristic development. It also suppresses gonadotropin release via negative feedback.
| Metabolism | Primarily hepatic via CYP3A4 and CYP2B6; metabolites include androsterone and etiocholanolone; excreted in urine. |
| Excretion | Renal (90% as glucuronide and sulfate conjugates), fecal (10%) |
| Half-life | Approximately 8 days (terminal elimination half-life of testosterone cypionate after intramuscular injection; due to slow release from oil depot, effective half-life in muscle is ~8 days with a longer terminal phase up to 3 weeks) |
| Protein binding | 97-99% bound to sex hormone-binding globulin (SHBG) and albumin |
| Volume of Distribution | Approximately 0.6-1.0 L/kg (reflects extensive distribution into tissues, including muscle and fat; total Vd ~4-9 L in adults) |
| Bioavailability | Intramuscular: 100% (administered as a depot injection in oil; undergoes first-pass metabolism if oral, but not relevant for IM route) |
| Onset of Action | Intramuscular: 2-3 days (time to reach peak serum concentrations and clinical effects; some effects may be noted within 24 hours) |
| Duration of Action | Intramuscular: 2-3 weeks (therapeutic effects persist due to prolonged release from the oily depot; dosing interval typically every 2-4 weeks) |
Intramuscular injection of 50-400 mg every 2-4 weeks, typically 200 mg every 2 weeks or 400 mg every 4 weeks.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment recommended; however, monitor fluid retention and hypertension in patients with severe renal impairment (GFR <30 mL/min). |
| Liver impairment | Child-Pugh A/B: No adjustment; Child-Pugh C: Contraindicated due to risk of hepatotoxicity. |
| Pediatric use | Not recommended for use in pediatric patients for hypogonadism; for delayed puberty, IM testosterone cypionate 50 mg every 4 weeks initially, titrating upward as needed. |
| Geriatric use | Start at lower end of dosing range (e.g., 50-100 mg every 2-4 weeks) due to increased risk of prostate enlargement and cardiovascular events; monitor serum testosterone levels and adjust accordingly. |
| 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 | Testosterone is excreted into breast milk in low concentrations; M/P ratio not reported. Theoretical risk of androgenic effects in male infants (e.g., masculinization). Use with caution only if maternal benefit outweighs potential risk. Consider alternative therapies while breastfeeding. |
| Teratogenic Risk |
■ FDA Black Box Warning
Prolonged use of high doses of testosterone has been associated with an increased risk of hepatocellular carcinoma.
| Common Effects | Acne |
| Serious Effects |
Known or suspected prostate carcinoma, male breast carcinoma, pregnancy, hypersensitivity to testosterone cypionate, severe hepatic/renal/cardiac disease (relative), hypercalcemia (in patients with immobility).
| Precautions | Risk of polycythemia (monitor hematocrit), edema in patients with cardiac/renal/hepatic disease, accelerated growth in prepubertal males (monitor bone age), gynecomastia, sleep apnea exacerbation, prostate hyperplasia/carcinoma (monitor PSA), decreased spermatogenesis, elevated blood pressure, hyperlipidemia. |
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| Testosterone cypionate is contraindicated in pregnancy. Androgenic effects may cause virilization of female fetus if exposed during organogenesis (first trimester). Second and third trimester exposure can also cause virilization. No adequate studies exist; use only if clearly needed for maternal condition, though use in pregnancy is generally avoided. |
| Fetal Monitoring | Monitor maternal: signs of virilization (hirsutism, voice deepening, clitoral enlargement), hepatic function, lipid profile, and possible edema. Monitor fetal: ultrasound for abnormal genital development if exposure occurs during pregnancy. Discuss risks of premature closure of epiphyseal plates in female fetuses. |
| Fertility Effects | Exogenous androgens suppress gonadotropin secretion, reducing testicular testosterone production in males (inhibiting spermatogenesis). In females, may suppress ovulation. Effects are generally reversible upon discontinuation. Chronic use may lead to persistent anovulation or oligospermia. |