R039 Pill Identification  The pill with an R039 imprint has been identified as 2mg Alprazolam (Xanax ) manufactured and supplied by Actavis. A four-sided 1-mg pill and yellow oval Xanax are the other shapes and strengths that are available. Alprazolam is a class of medications called benzodiazepines which act on the brain and nerves (central nervous system) to produce a calming effect. […]