NR566 Week 1 Study Outline Chapter 21: Drugs Affecting the Endocrine System

NR566 Week 1 Study Outline Chapter 21: Drugs Affecting the Endocrine System Bisphosphonates • Drugs: etidronate (Didronel), pamidronate (Aredia), risedronate (Actonel) alendronate (Fosamax), tiludronate (Skelid), zoledronic acid (Zometa), ibandronate (Boniva) • Used for bone support, most commonly used • Pharmacodynamics  Adhere to bone, inhibit osteoclastic activity, potent inhibitors of both normal and abnormal bone resorption o Etidronate (Didronel): reduces both bone resorption and bone formation because formation is coupled with resorption o Pamidronate (Aredia) (available as IV only) o and risedronate (Actonel): inhibit bone resorption with out inhibiting bone formation and mineralization o Alendronate (Fosamax): highly selective inhibitor of bone resorption 1  100 to 500 time more potent than the other drugs  Does not interfere with osteoclastic recruitment or attachment but does inhibit osteoclastic activity o Tiludronate (Skelid): inhibits protein-tyrosine-phosphatease, results in detachment of osteoclasts from the bone surface  Inhibits the osteoclastic proton pump o Zoledronic acid (Zometa): inhibits osteoclastic activity and induces osteoclast apoptosis  Also inhibits the increased osteoclastic activity and skeletal calcium release induced by various stimulatory factors release by tumors  Only available as IV formulation o Ibandronate (Boniva): inhibits osteoclast activity and reduces bone resorption and turnover based on its affinity for hydroxyapatite (part of the bone matrix)