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 and have an increased risk for fractures or who cannot take or did not respond to other medications for osteoporosis. 

Prolia is in a class of medications called RANK ligand inhibitors. It works by decreasing bone breakdown and increasing bone strength and density (thickness).

Prolia comes as a solution (liquid) to be injected under the skin in your upper arm, upper thigh, or stomach area. It is usually injected by a doctor or nurse in a medical office or clinic. When it is used to treat osteoporosis, it is usually given once every 6 months. When it is used to reduce fractures from cancer that has spread to the bones, it is usually given once every 4 weeks.

Some common side effects of Prolia include joint pain, back pain, pain in your arms and legs and muscle pain.