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) |
| Molecular Weight | 412.60 Da (as testosterone cypionate; testosterone base 288.42 Da) |
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 | Testosterone cypionate is contraindicated in pregnancy due to virilization of female fetus. Androgens can cause pseudohermaphroditism in females. |
| 2nd trimester | Same as T1. Risk of virilization persists throughout gestation. |
| 3rd trimester | Same as T1 and T2. Avoid use during entire pregnancy. |
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 |
| Placental transfer | Testosterone crosses the placenta readily. Androgenic effects on female fetus can occur with any trimester exposure. |
| Breastfeeding |
■ 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 |
PregnancyBreast cancer in menProstate cancerHypersensitivity to testosterone or any componentFemale with breast cancer (with hypercalcemia)
| 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. |
| Food/Dietary | No significant food interactions. Limit alcohol consumption as it may increase risk of liver damage. Grapefruit juice may interfere with testosterone metabolism; avoid excessive intake. |
Loading safety data…
| Testosterone cypionate is excreted in human milk. Use during breastfeeding may cause adverse effects in the infant, including virilization. The decision to breastfeed while on this therapy should be based on the importance of the drug to the mother and potential risks to the infant. |
| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | 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. |
| Clinical Pearls | Testosterone cypionate is a long-acting injectable androgen. Monitor hematocrit and hemoglobin due to risk of polycythemia. Use with caution in patients with sleep apnea, benign prostatic hyperplasia, or cardiovascular disease. Check serum testosterone levels 1 week after injection to assess adequacy. For men with hypogonadism, avoid in those with untreated hyperprolactinemia or pituitary tumor. |
| Patient Advice | Inject deeply into the muscle (gluteal or thigh) to reduce pain and risk of abscess. · Do not use if you have breast cancer, prostate cancer, or are pregnant. · Report swelling in ankles, difficulty breathing, or severe headache immediately. · Do not take with blood thinners like warfarin without consulting your doctor. · Expect possible mood changes, increased acne, or hair loss. Monitor for priapism. · Regular blood tests are required to check red blood cell count, liver function, and prostate health. |