Bisphosphonates are a class of drugs that prevent bone loss and are used to treat bone metastases, osteoporosis, and Paget's disease. They have a high affinity for hydroxyapatite crystals in bone and work by inhibiting bone resorption. There are two types - non-nitrogenous bisphosphonates which induce osteoclast apoptosis, and nitrogenous bisphosphonates which inhibit protein prenylation in osteoclasts. Common indications include postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, and bone metastases. While generally well-tolerated, side effects can include upset stomach, esophagitis, and osteonecrosis of the