Nandrolone decanoate is a parenteral anabolic steroid. It is primarily used to treat anemia, chronic renal failure, osteoporosis and AIDS-associated wasting syndrome. This agent is known to increase hemoglobin and red cell mass. With the development of recombinant human erythropoietin, nandrolone decanoate use in anemia associated with chronic renal failure has declined. It has also been the subject of drug misuse and abuse, often producing adverse effects such as changes in libido, hepatotoxicity, increased risk of cardiovascular disease, and antisocial behavior. Some of the masculinizing effects in women can be irreversible. Nandrolone decanoate was approved by the FDA in 1983 and became a controlled substance in 1991.
Mechanism of Action: Nandrolone decanoate shares the actions of endogenous androgens such as testosterone. Exogenous androgens such as nandrolone decanoate promote protein anabolism and stimulate appetite which results in a reversal of catabolic processes and negative nitrogen balance. Increases in lean body mass in patients with cachexia (e.g., malnourished dialysis patients) and decreased bone resorption and increased bone density in patients with osteoporosis are often noted. Blood glucose, erythrocyte production, and the balance of calcium are also affected by androgens. Increased erythrocyte production is apparently due to enhanced production of erythropoietic stimulating factor. Patients with anemia associated with renal disease will have increases in red blood cell volume and hemoglobin after receiving nandrolone decanoate.
Since nandrolone decanoate has actions similar to endogenous androgens, administration of nandrolone decanoate has the possibility of causing serious disturbances of growth and sexual development if given to young children and causing unwanted adverse effects in women. Exogenous androgens suppress gonadotropin-releasing hormone, thereby reducing the gonadotropic function of the pituitary through a negative-feedback mechanism. This results in a reduction of endogenous testosterone, luteinizing hormone, and follicle-stimulating hormone. Exogenous androgens may also have a direct effect on the testes. Reversible increases in low-density lipoproteins (LDL) and decreases in high-density lipoproteins (HDL) also occur.
Pharmacokinetics: Nandrolone decanoate is administered intramuscularly. In the systemic circulation, nandrolone decanoate is rapidly hydrolyzed to free nandrolone by plasma esterases. Nandrolone has high lipid solubility and can rapidly diffuse into cells. Nandrolone is subsequently metabolized in the liver via reduction and oxidation which is similar to the metabolism of testosterone. Data on the excretion of the parent compound and metabolites are lacking. The plasma clearance of nandrolone is approximately 1.6 L/hour/kg and the elimination half-life of the parent compound is 6 to 8 days.
Route-Specific Pharmacokinetics: Intramuscular Route:Following intramuscular injection, nandrolone decanoate is slowly released from the intramuscular depot at a relatively constant rate over approximately 4 days. A 100-mg dose produces peak serum concentrations in 3—6 days.