Bisphosphonates

Bisphosphonates in hyperparathyroidism

Bisphosphonates (alendronate, zoledronic acid and risedronate) are analogs of pyrophosphate with a carbon instead of oxygen atom (P-O-P).

They attach to the bone crystals and are absorbed by osteoclasts, which breakdown bone. Within the osteoclast, bisphosphonates interfere in the normal function and induce apoptosis. In addition, they decrease the depth of resorption cavities, therefore it slows remodelling rate and decreases resorption at each site of bone turnover. Thus, by inhibiting bone resorption, bisphosphonates freeze the cycle of bone remodelling.

Major side effects of the oral bisphosphonates include GI-complaints since these drugs require administration on an empty stomach. Intravenously administered bisphosphonates also display GI-complaints as adverse effects, but infections, parathyroid problems and headaches also occur often.

See also bisphosphonates in osteoporosis and oncology.