Prolia and Reclast for Osteoporosis
What is Prolia and Reclast for Osteoporosis?
Osteoporosis is a loss of bone, weakening the skeleton. Bone is a living, dynamic tissue which is being constantly broken down and rebuilt, enabling fractures to heal and bones to be remodeled and strengthened in athletes and laborers, for example.
The cells that build new bone are called “osteoblasts”. The cells that break the bone down are called “osteoclasts”.
The balance between the activity of these two cells is of great importance in bone structure and strength. In children, when the bones are growing, osteoblasts are more active and build new bone. In adults, the osteoclasts, which absorb the bone, are more active leading to a loss of bone strength. This is especially true in post-menopausal women.
Two drugs are available to help restore the balance between the osteoblasts and the osteoclasts in bone. These are Prolia and Reclast.
- Generic name: Denosumab
- Conditions in which denosumab is used: denosumab is used to treat osteoporosis, medication-induced bone loss, metastatic cancer in bone and giant cell tumor of the bone. It seems to work better in females than in males.
- How it works: The number of active osteoclasts depends on a growth factor called “RANKL”. In osteoporosis a natural inhibitor of RANKL is decreased. Denosumab is a monoclonal antibody that binds to RANKL and inhibits the production of osteoclasts, thus restoring the balance between bone breakdown and bone growth, and reducing bone degradation.
- Possible side effects of denosumab: Common side effects are joint and muscle pain in the arms and legs. Allergic reactions and an increase in infections may occur. RANKL is also a growth factor for cells of the immune system, thus explaining and increased risk of infection. Some people develop low blood calcium (as bone is rebuilt), so denosumab is not given to patients with existing low blood calcium or a Vitamin D deficiency. Osteonecrosis of the jaw bone (after dental procedures) and atypical fractures of the femur have been reported.
- Generic name: Zoledronic acid
- Conditions in which zoledronic acid is used: Zoledronic acid is used to treat a number of bone diseases. These include osteoporosis, bone breakdown and high blood calcium due to cancer and Paget’s disease of the bone. Some studies show a direct effect on osteosarcoma (bone cancer) cells, too.
- How it works: Zoledronic acid is a drug in the bisphosphonate class and is, by far, the most potent. The drug goes to sites of high bone turnover where it inhibits osteoclast-mediated bone resorption. It does this by inhibiting an enzyme in osteoclasts responsible for dissolving bone.
- Possible side effects of zoledronic acid: Common side effects are fever, joint pain, high blood pressure, diarrhea and fatigue Serious side effects may include kidney damage, low blood calcium and osteonecrosis of the jaw. Zoledronic acid is not given to patients with poor kidney function or existing low blood calcium levels.