Denosumab is a medication a doctor may prescribe to treat bone loss in patients with osteoporosis or medical conditions linked with bone loss. The drug also has regulatory approval for the treatment of metastases in the bone. The -mab ending indicates that it is a monoclonal antibody. This drug is available by prescription only, and there are some special precautions patients must take before they can safely begin treatment with denosumab.
This medication works by targeting receptor activator of nuclear factor kappa-B ligand (RANKL), a protein the body produces to regulate the activity of osteoclasts, the cells that break down bone. In patients with bone loss, the osteoclasts work more quickly than the body can deposit new bone, resulting in a net loss. Denosumab slows the rate of bone loss, allowing patients to retain more bone mass. This increases bone strength and durability.
For patients with osteoporosis who are at high risk of fractures, this medication can reduce the chance of fracturing a major bone. This will prevent significant medical complications. Fractures of the hip in particular can lead to a cascading series of health problems for older patients, and prevention of such injuries can improve quality of life as well as a patient's lifespan. Denosumab can also be useful when bone loss is caused by medical treatment for another condition, or in the management of metastatic growths on the bones.
Before taking this medication, a patient needs to have normal calcium levels. Doctors may recommend periodically rechecking calcium levels because denosumab can cause hypocalcemia, where a patient does not have enough calcium. Other side effects can include constipation, rashes, joint pain, and infections, particularly in the urinary and respiratory tracts. Patients who do experience fractures while on denosumab will also notice a slower healing time.
Patients on denosumab may be at risk of statistically unusual fractures in the future. The medication changes bone growth and deposition over time, and in patients who take it for an extended period of time, the risk of fractures can actually be elevated because of the biological changes caused by the drug. If this is a concern, a doctor will discuss it with a patient. Many drugs developed to treat bone loss have the same side effect, illustrating the complexities in treating aging adults as well as astronauts, the other group within the population that runs an increased risk of losing bone density and developing potentially serious fractures.