Calcitonin in Paget's disease

Calcitonin acts directly on calcitonin receptors expressed on osteoclasts, there by inhibiting bone resorption

• the salmon form is preferred to the porcine form as it is more suitable for long-term therapy
• given parenterally since calcitonin is rapidly degraded in the gastrointestinal tract (1)
• associated side effects include flushing, nausea and vomiting

Prolonged use of calcitonin may lead to the development of anti-calcitonin antibodies resulting in patients becoming refractory to treatment.

Unlike with bisphosphonate treatment, the markers of disease activity (serum alkaline phosphatase and urinary hydroxyproline) rarely return to normal levels (1).

Due to its partial response, acquired resistance (in about 25% of patients), bothersome side effects and a short-lived action, bisphosphonates have now replaced calcitonin as the medical treatment of choice for Paget's disease (2,3). However it may be useful in those patients in whom bisphosphonates are not tolerated or have proven to be ineffective (1).

Reference:

• (1) Selby PL  et al. Guidelines on the management of Paget's disease of bone. Bone. 2002;31(3):366-73.
• (2) Michou L, Brown JP. Emerging strategies and therapies for treatment of Paget's disease of bone. Drug Des Devel Ther. 2011;5:225-39
• (3) Whyte MP. Clinical practice. Paget's disease of bone. N Engl J Med.2006;355(6):593-600.