**5. Zoledronic acid**

Over the last 10 years, there has also been growing interest in the issue of bone health in prostate cancer as it is known that both androgen deprivation therapy, and bony metastases can promote bone destruction. Zoledronic acid, is a nitrogen-containing bisphosphonate that inhibits osteoclast-mediated bone resorption. In a randomized placebo controlled clinical trial in men with CRPC and bone metastases, zoledronic acid reduced skeletal related events and decreased bone pain leading to its approval by the FDA in 2002 (Saad *et al.*, 2002). Bone resorption is a process that is dependent on RANK Ligand, a protein that acts as the primary mediator of osteoclast formation, function and survival. Preclinical models have demonstrated that inhibiting RANK Ligand significantly improves cortical and trabecular bone density, volume and strength. Studies with a novel bone targeting agent known as Denosumab have been encouraging, and offers another agent to address the bone complications of prostate cancer.
