A humanized monoclonal antibody directed against the receptor activator of nuclear factor kappa beta ligand (RANKL) with antiosteoclast activity. Denosumab specifically binds to RANKL and blocks the interaction of RANKL with RANK, a receptor located on osteoclast cell surfaces, resulting in inhibition of osteoclast activity, a decrease in bone resorption, and a potential increase in bone mineral density. RANKL, a protein expressed by osteoblastic cells, plays an important role in osteoclastic differentiation and activation.

Why is this medication prescribed?

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) and have an increased risk for fractures (broken bones) or who cannot take or did not respond to other medications for osteoporosis. Denosumab injection (Xgeva) is used to reduce fractures from cancer that began in another part of the body but has spread to the bones. Denosumab injection (Xgeva) is not used to reduce fractures from multiple myeloma (cancer that begins in the plasma cells [a type of white blood cell that produces substances needed to fight infection]). Denosumab injection is in a class of medications called RANK ligand inhibitors. It works by decreasing bone breakdown and increasing bone strength and density (thickness).

How should this medicine be used?

Denosumab injection comes as a solution (liquid) to be injected subcutaneously (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 denosumab injection is used to treat osteoporosis, it is usually given once every 6 months. When denosumab injection is used to reduce fractures from cancer that has spread to the bones, it is usually given once every 4 weeks.

Your doctor will tell you to take supplements of calcium and vitamin D while you are being treated with denosumab injection. Take these supplements exactly as directed.

When denosumab injection is used to treat osteoporosis, your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with denosumab injection and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer’s website to obtain the Medication Guide.

Other uses for this medicine:

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

• tell your doctor and pharmacist if you are allergic to denosumab, any other medications, latex, or any of the ingredients in denosumab injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• you should know that denosumab injection is available under the brand names Prolia and Xgeva. Be sure to tell your doctor if you are being treated with either of these medications.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: anticoagulants (‘blood thinners’) such as heparin; cancer chemotherapy medications; medications for seizures such as phenytoin (Dilantin, Phenytek); medications that suppress the immune system such as azathioprine (Imuran), cyclosporine (Gengraf, Neoral, Sandimmune), methotrexate (Rheumatrex, Trexall), sirolimus (Rapamune), and tacrolimus (Prograf); oral steroids such as dexamethasone (Decadron, Dexpak), methylprednisolone (Medrol), and prednisone (Sterapred); or vitamin A (Aquasol A). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have hypocalcemia (lower than normal level of calcium in your blood). Your doctor will probably tell you not to receive denosumab injection.
• tell your doctor if you have or have ever had anemia (condition in which the red blood cells do not bring enough oxygen to all the parts of the body); cancer; any type of infection, especially in your mouth; problems with your mouth, teeth, gums, or dentures; any condition that stops your blood from clotting normally; any condition that decreases functioning of your immune system; thyroid surgery; surgery to remove part of your small intestine; problems with your stomach or intestine that make it difficult for your body to absorb nutrients; or thyroid or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while receiving denosumab injection, call your doctor.
• you should know that denosumab injection may cause serious problems with your jaw, especially if you have dental surgery or treatment while you are being treated with denosumab injection. Talk to your doctor and dentist before having any dental treatments while you are receiving this medication. A dentist should examine your mouth and perform any needed treatments before you start treatment with denosumab injection. Be sure to brush your teeth, floss, and clean your mouth properly while you are being treated with denosumab injection.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?

If you miss an appointment to receive an injection of denosumab, you should call your healthcare provider as soon as possible. The missed dose should be given as soon as it can be rescheduled. When denosumab injection is used for osteoporosis, after you receive the missed dose, your next injection should be scheduled 6 months from the date of your last injection.

What side effects can this medication cause?

• red, dry, or itchy skin
• rash
• oozing or crusty blisters on skin
• peeling skin
• back pain
• pain in your arms or legs
• muscle pain

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately: 

• muscle stiffness or spasms
• tingling in your fingers, toes, or around your mouth
• fever or chills
• excessive sweating
• tiredness
• redness, tenderness, swelling or warmth of area of skin
• ear drainage or severe pain
• frequent or urgent need to urinate
• burning feeling when you urinate
• pain, numbness, swelling, or drainage from mouth, teeth, or jaw
• slow healing of the mouth or jaw
• ongoing pain, that begins in the upper left or middle of the stomach but may spread to the back
• nausea
• vomiting
• fast heart rate
• difficulty breathing

Denosumab injection may cause certain bones to break and broken bones to heal slowly. Denosumab injection may also impair bone growth and prevent teeth from coming in properly in children. Talk to your doctor about the risks of receiving this medication.

Denosumab injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

*Source: National Cancer Institute
*Source: Medline Plus