As such, the researchers stated, "although oxandrolone cannot be implicated as stimulatory [in] gynecomastia", a possible relationship should be considered in clinicians using oxandrolone in adolescents for growth stimulation.Uniquely among 17α-alkylated AASs, oxandrolone shows little to no hepatotoxicity, even at high doses. No cases of severe hepatotoxicity have been singularly attributed to oxandrolone. However, elevated liver enzymes have been observed in some people, particularly with high doses and/or prolonged treatment, although they return to normal ranges following discontinuation. Interactions
Oxandrolone greatly increases warfarins blood-thinning effect, sometimes dangerously so. In April 2004, Savient Pharmaceuticals published a safety alert through the FDA warning healthcare professionals of this. Oxandrolone can also inhibit the metabolism of oral hypoglycemic agents. It may worsen edema when taken alongside corticosteroids or adrenocorticotropic hormone. Pharmacology
Pharmacodynamics
Like other AASs, oxandrolone is an agonist of the androgen receptor, similar to androgens such as testosterone and DHT. The relative binding affinity of oxandrolone for the androgen receptor is about 0.8% of that of metribolone. Activation of the androgen receptor stimulates protein synthesis, which increases muscle growth, lean body mass, and bone mineral density.Compared to testosterone and many other AASs, oxandrolone is less androgenic relative to its strength as an anabolic. Oxandrolone has about 322 to 633% of the anabolic potency and 24% of the androgenic potency of methyltestosterone. Similarly, oxandrolone has as much as 6 times the anabolic potency of testosterone and has significantly reduced androgenic potency in comparison.
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 oxandrolones 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.