Denosumab injection (Prolia) is used to treat osteoporosis (a condition in which the bones become thin and weak and break easily) in women who have undergone menopause (''change of life;'' end of menstrual periods) who have an increased risk for fractures (broken bones) or who cannot take or did not respond to other medication treatments for osteoporosis. to treat men who have an increased risk for fractures (broken bones) or who cannot take or did not respond to other medication treatments for osteoporosis. treat osteoporosis that is caused by corticosteroid medications in men and women who will be taking corticosteroid medications for at least 6 months and have an increased risk for fractures or who cannot take or did not respond to other medication treatments for osteoporosis. to treat bone loss in men who are being treated for prostate cancer with certain medications that cause bone loss, to treat bone loss in women with breast cancer who are receiving certain medications that increase their risk for fractures. Denosumab injection (Xgeva) is used to reduce the risk of fractures in people who have multiple myeloma (cancer that begins in the plasma cells and causes bone damage), and in people who have certain types of cancer that began in another part of the body but has spread to the bones. in adults and some adolescents to treat giant cell tumor of bone (GCTB; a type of bone tumor) that cannot be treated with surgery. to treat high calcium levels that are caused by cancer in people who did not respond to other medications.Denosumab injection is in a class of medications called RANK ligand inhibitors. It works to prevent bone loss by blocking a certain receptor in the body to decrease bone breakdown. It works to treat GCTB by blocking a certain receptor in the tumor cells which slows the tumor growth. It works to treat high calcium levels by decreasing bone breakdown as the breakdown of bones releases calcium.