DURABOLIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for DURABOLIN (DURABOLIN).
DURABOLIN (nandrolone phenpropionate) is an anabolic steroid that binds to androgen receptors, increasing protein synthesis and nitrogen retention, promoting muscle growth and bone density. It also stimulates erythropoietin production, increasing red blood cell mass.
| Metabolism | Hepatic metabolism via reduction and conjugation; primarily excreted in urine as metabolites (e.g., 19-norandrosterone and 19-noretiocholanolone). |
| Excretion | Primarily renal: 90% as metabolites (glucuronide and sulfate conjugates), 10% unchanged; negligible biliary/fecal elimination. |
| Half-life | Terminal elimination half-life: 4-6 days (intramuscular depot), reflecting slow release from injection site and enterohepatic recirculation; clinical steady-state achieved after 3-6 weeks. |
| Protein binding | 85-95% bound to sex hormone-binding globulin (SHBG) and albumin; high affinity for SHBG, reducing free active fraction. |
| Volume of Distribution | 4-6 L/kg, indicating extensive tissue distribution, particularly to skeletal muscle, bone, and prostate. |
| Bioavailability | Intramuscular: ~100% (depot formulation); oral: negligible (<1% due to first-pass hepatic metabolism). |
| Onset of Action | Intramuscular: 24-72 hours for androgen effects; myotrophic effects manifest within 1-2 weeks. |
| Duration of Action | Intramuscular: 2-4 weeks for single dose; doses repeated every 2-3 weeks for sustained effects due to slow release and long half-life. |
100-200 mg intramuscularly every 1-2 weeks for testosterone replacement; for wasting syndromes, 50-100 mg intramuscularly weekly.
| Dosage form | INJECTABLE |
| Renal impairment | No specific guidelines; use caution in severe impairment (CrCl <30 mL/min) due to fluid retention and potential edema. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use due to risk of cholestasis and hepatotoxicity. |
| Pediatric use | Not recommended in children due to premature epiphyseal closure and potential virilization; limited data, use only under expert supervision for delayed growth. |
| Geriatric use | Initiate at lowest effective dose (e.g., 50 mg IM every 2 weeks) due to increased risk of prostatic hypertrophy, fluid retention, and polycythemia. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for DURABOLIN (DURABOLIN).
| Breastfeeding | Nandrolone is excreted into breast milk. The milk-to-plasma ratio is not established. Androgens may suppress lactation and cause virilization in the nursing infant. Use during breastfeeding is contraindicated. |
| Teratogenic Risk | DURABOLIN (nandrolone) is contraindicated in pregnancy. Androgens can cause virilization of the female fetus. First trimester exposure risks clitoromegaly, labial fusion, and urogenital sinus abnormalities. Second and third trimester exposure may lead to clitoromegaly and advanced bone age. Fetal growth restriction and preterm birth are also reported. |
■ FDA Black Box Warning
Anabolic steroids may cause peliosis hepatis, liver cell tumors, and blood lipid changes associated with increased cardiovascular risk. Prolonged use can lead to azoospermia, oligospermia, and impotence. Not approved for enhancing athletic performance.
| Common Effects | Edema swelling Nausea Breast enlargement Acne |
| Serious Effects |
Known hypersensitivity to nandrolone or any component, pregnant or breastfeeding women, men with carcinoma of the breast or prostate, nephrotic syndrome, hypercalcemia, severe hepatic dysfunction, and patients with a history of myocardial infarction or coronary artery disease.
| Precautions | Risk of hepatic dysfunction, peliosis hepatis, hepatocellular carcinoma, hyperlipidemia, cardiovascular disease, edema, hypertension, glucose intolerance, premature closure of epiphyseal growth plates in children, virilization in women, and prostate hypertrophy in men. Monitor liver function, lipid profile, and hematocrit. Use with caution in patients with cardiac, renal, or hepatic disease. |
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| Fetal Monitoring | Maternal monitoring: liver function tests, lipid profile, blood glucose, blood pressure, signs of virilization (e.g., hirsutism, voice deepening). Fetal monitoring: ultrasound for growth, amniotic fluid volume, and signs of virilization; consider fetal karyotyping if exposure occurs. |
| Fertility Effects | In females, nandrolone may disrupt ovulatory cycles and cause amenorrhea due to suppression of gonadotropins. In males, exogenous androgens suppress spermatogenesis and may reduce fertility. Reversibility is variable; prolonged use may lead to persistent oligospermia or azoospermia. |