Evenity (romosozumab) and Prolia (denosumab) are prescription drugs used to treat osteoporosis in certain people. Both are biologic drugs and not available as biosimilars. Evenity and Prolia are used to treat osteoporosis in postmenopausal women. Both come as a liquid solution given by a healthcare professional as an injection under the skin. They can cause some of the same side effects. Evenity has a boxed warning for the risk of heart attack, stroke, or death due to cardiovascular problems. Prolia has a boxed warning for the risk of severe low blood calcium, especially in people with advanced kidney disease. Note that treatment with Evenity is limited to 12 months, while Prolia has no such limit. If treatment exceeds 12 months, doctors typically switch from Evenity to Prolia.