A multidose study of oxandrolone, given as 5 or 10 mg bid in 15 healthy subjects concurrently treated with warfarin, resulted in a mean increase in S-warfarin half-life from 26 to 48 hours and AUC from to ng • hr/mL; similar increases in R-warfarin half-life and AUC were also detected. Microscopic hematuria (9/15) and gingival bleeding (1/15) were also observed. A -fold decrease in the mean warfarin dose from mg/day to mg/day (approximately 80-85% reduction of warfarin dose), was necessary to maintain a target INR of . When oxandrolone therapy is initiated in a patient already receiving treatment with warfarin, the INR or prothrombin time (PT) should be monitored closely and the dose of warfarin adjusted as necessary until a stable target INR or PT has been achieved.
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 AAS 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-δ 2 -DHT), methasterone (2α,17α-dimethyl-DHT), methyl-1-testosterone (17α-methyl-δ 1 -DHT), and methylstenbolone (2,17α-dimethyl-δ 1 -DHT).   
In July 2011, FDA began a pilot program to notify people of drug recalls before they are classified in an effort to expedite notifications of human drug product recalls to the public. FDA is now able to accomplish the goal of expedited notification within the Enforcement Report. These recalls are identified within the Enforcement Report by the label of “Not Yet Classified” in the “Classification” column. It is also possible to search the Enforcement Report for these “Not Yet Classified” recalls using the filter drop down menu. Therefore, as of September 15, 2017 FDA will discontinue the pilot program, and will no longer post drug recalls that are pending classification on this webpage. To see posted recalls that are pending classification go to the weekly Enforcement Report.