|ATC code||A14AA08 (WHO)|
|Biological half-life||9 hours|
|Chemical and physical data|
|Molar mass||306.44 g/mol|
|3D model (Jmol)||Interactive image|
|(what is this?)|
Oxandrolone (brand names Oxandrin, Anavar, Lonavar, others), is a synthetic, orally active anabolic-androgenic steroid (AAS) that first become available as a prescription drug in the United States in 1964. It is a 17α-methylated derivative of dihydrotestosterone (DHT) that has an oxygen atom in place of the carbon at the 2 position.
Researchers and medical professionals have used oxandrolone to treat a wide variety of disorders. These include idiopathic short stature, Turner syndrome, body mass loss from catabolic illness or long-term corticosteroid treatment, severe burns, surgical or general trauma, osteoporosis, anemia, hereditary angioedema, HIV/AIDS-induced wasting, alcoholic hepatitis, and hypogonadism.
Oxandrolone is well-established as a safe treatment for patients recovering from severe burns. Medical research has also established oxandrolone's efficacy in aiding the development of girls with Turner syndrome. Although oxandrolone has long been used to accelerate growth in children with idiopathic short stature, it is unlikely to increase adult height and in some cases may even decrease it. Oxandrolone has therefore largely been replaced by growth hormone for this use.
Some bodybuilders use oxandrolone for its muscle-building properties, usually purchasing it from black market suppliers. This is illegal in the United States, Canada, the United Kingdom, and many other countries.
Oxandrolone has been researched and prescribed as a treatment for a wide variety of conditions. Oxandrolone is FDA-approved for treating osteoporosis, aiding weight gain, and counteracting the catabolic effect of long-term corticosteroid treatment. As of 2016, it is often prescribed off-label to quicken recovery from severe burns, aid the development of girls with Turner syndrome, and counteract HIV/AIDS-induced wasting.
Oxandrolone increases both short-term and long-term outcomes in patients recovering from severe burns. Most evidence shows that it reduces the amount of time spent hospitalized and that improved muscle and bone recovery are still measurable a year after injury.
Research suggests that oxandrolone is also effective in the treatment of alcoholic hepatitis.
Like other anabolic steroids, oxandrolone may worsen hypercalcemia by increasing osteolytic bone resorption. When taken by pregnant women, oxandrolone may have unintended effects such as masculinization on the fetus.
Although some orally-administered anabolic steroids are hepatotoxic, oxandrolone causes little or no detectable stress to burn victims' livers at clinical doses. This supports the notion common among bodybuilders that oxandrolone is less hepatotoxic than most common oral anabolic steroids.
Women who are administered oxandrolone may experience virilization, the non-reversible development of masculine features such as voice deepening, hirsutism, menstruation abnormalities, male-pattern hair loss, and clitoral enlargement. Oxandrolone may disrupt growth in children, reducing their adult height. Because of these side effects, doses given to women and children are chosen carefully and patients are usually monitored for virilization and growth abnormalities.
Like other androgens, oxandrolone can cause or worsen acne and priapism (unwanted or prolonged erections). Oxandrolone can also reduce males' fertility, another side effect common among androgens. In an attempt to compensate for the exogenous increase in androgens, the body may reduce testosterone production via testicular atrophy and inhibition of gonadotropic activity.
Oxandrolone greatly increases warfarin's 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 adrenal cortical steroids or adrenocorticotropic hormone (ACTH).
Mechanism of action
Compared to testosterone and most other anabolic steroids, oxandrolone is less androgenic relative to its strength as an anabolic. This often motivates its medical use in children and women because less androgenic effect implies less risk of virilization. The bodybuilding community also considers this fact when choosing between steroids.
Children with idiopathic short stature or Turner syndrome are given doses of oxandrolone far smaller than those given to burn patients. Researchers have chosen dose ranges for children with great care in order to minimize the likelihood of virilization and premature maturation. Most adults treated with oxandrolone receive moderate doses. Bodybuilders often take doses much higher than these.
Oxandrolone is generally administered at least once daily.
Oxandrolone was first made by Raphael Pappo and Christopher J. Jung while at Searle Laboratories (now part of Pfizer). The researchers first described the chemical in 1962. They were immediately interested in oxandrolone's very weak androgenic effect relative to its anabolic effect. It was released 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 who, following successful clinical trials in 1995, released it under the tradename Oxandrin. BTG subsequently won approvals for orphan drug status by the Food and Drug Administration (FDA) 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
In the United States, oxandrolone is categorized as a Schedule III controlled substance under the Controlled Substances Act along with many other anabolic steroids. It is a Schedule IV controlled substance in Canada and a Schedule 4 Controlled Drug in the United Kingdom.
Many bodybuilders and athletes use oxandrolone for its muscle-building properties. Oxandrolone is much less androgenic than anabolic, so women and those seeking less intense steroid regimens use it particularly often. Many also value oxandrolone's low hepatotoxicity relative to most other orally active steroids.
The original brand name of oxandrolone was Anavar. Oxandrin is often used as a generic trade name. Oxandrolone has also been sold under the trade names Lonavar (Argentina, Australia), Lipidex (Brazil), Antitriol (Spain), Anatrophill (France), Protivar, and Vasorome. Additional brand names exist for products that are manufactured for the steroid black market.
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