hepatotoxic than other 17α-alkylated AASs, which may be due to differences in metabolism. Pharmacokinetics The oral bioavailability of oxandrolone is 97%. Its plasma protein binding is 94 to 97%. The drug is metabolized primarily by the kidneys and to a lesser extent by the liver. Oxandrolone is the only AAS that is not primarily or extensively metabolized by the liver, and this is thought to be related to its diminished hepatotoxicity relative to other AASs. Its elimination half-life is reported as 9.4 to 10.4 hours, but is extended to 13.3 hours in the elderly. About 28% of an oral dose of oxandrolone is eliminated unchanged in the urine and 3% is excreted in the feces. Chemistry Oxandrolone is a synthetic androstane steroid and a 17α-alkylated derivative of DHT. It is also known as 2-oxa-17α-methyl-5α-dihydrotestosterone (2-oxa-17α-methyl-DHT) or as 2-oxa-17α-methyl-5α-androstan-17β-ol-3-one, and is DHT with a methyl group at the C17α position and the C2 carbon replaced with an oxygen atom. Closely related AASs include the marketed AAS mestanolone (17α-methyl-DHT), oxymetholone (2-hydroxymethylene-17α-methyl-DHT), and stanozolol (a 2,3-pyrazole A ring-fused derivative of 17α-methyl-DHT) and the never-marketed/designer AAS desoxymethyltestosterone (3-deketo-17α-methyl-δ2-DHT), methasterone (2α,17α-dimethyl-DHT), methyl-1-testosterone (17α-methyl-δ1-DHT), and methylstenbolone (2,17α-dimethyl-δ1-DHT). History Oxandrolone was first made by Raphael Pappo and Christopher J. Jung while at Searle Laboratories (now part of Pfizer). The researchers first described the drug in 1962. They were immediately interested in oxandrolone's very weak androgenic effects relative to its anabolic effects. It was introduced as a pharmaceutical drug in the United States in 1964. The drug was prescribed to promote muscle regrowth in disorders which cause involuntary weight loss, and is used as part of treatment for HIV/AIDS. It had also been shown to be partially successful in treating cases of osteoporosis. However, in part due to bad publicity from its illicit use by bodybuilders, production of Anavar was discontinued by Searle Laboratories in 1989. It was picked up by Bio-Technology General Corporation, which changed its name to Savient Pharmaceuticals, which following successful clinical trials in 1995, released it under the brand name Oxandrin. BTG subsequently won approvals for orphan drug status by the Food and Drug Administration for treating alcoholic hepatitis, Turner syndrome, and HIV-induced weight loss. It is also indicated as an offset to protein catabolism caused by long-term administration of corticosteroids. Society and culture Generic names Oxandrolone is the generic name of the drug and its , , , , , , and ,