8th January 2024

Bisphosphonates

Bisphosphonates include pamidronate and zoledronic acid. They inhibit the activity of osteoclasts, reducing the breakdown of bone. As such, they are used in hypercalcaemia and cancer-related bone pain.

They can be used prophylactically orally or IV to prevent bone pain or fractures in patients with breast cancer and myeloma. Treatment of bone pain, however, is given IV due to poor bioavailability orally. It is generally used where there is widespread metastatic disease, as radiotherapy is preferred where this is localised. Pain relief can take about two weeks and has a variable duration dependent on the agent chosen.

Patients may suffer transient worsening of bone pain following administration of bisphosphonates. Up to 50% of patients develop a viral-like illness, including fevers, 48 hours after administration. For the exam, the most significant side effect to be aware of is the development of osteonecrosis of the jaw. This is more common in those with previous dental procedures and poor dental health – so a dental review may be required before administration.