Mechanism of action
The mechanism of antiresorptive action of pamidronate is not well understood. Several factors are thought to contribute to this action. Pamidronate adsorbs to calcium phosphate (hydroxy-apatite) crystals in bone and may directly block dissolution of this mineral component of bone. Inhibition of osteoclast activity also contributes to inhibition of bone resorption. Pamidronate inhibits the accelerated bone resorption resulting from osteoclast hyperactivity induced by various tumours and this is of significance in treatment of malignancy induced hyper-calcaemia.