The hydrochloride salt form of oxymorphone, a semisynthetic opioid with a potent analgesic property. Oxymorphone hydrochloride binds to and activates opiate receptors, specifically mu-receptors, in the central nervous system (CNS). This results in sedation, analgesia, decreased gastrointestinal motility, and respiratory depression. or A radioactive form of the element phosphorus used in the treatment of cancer.