①simple, non-nitrogenous bisphosphonates
②potent, nitrogenous bisphosphonates

①ATP is built up in osteoclast→apoptosis→less bone resorption
e.g.etidronate

②inhibit osteoclast's mevalonate passway→disrupts synthesis of cholesterol→osteoclast becomes nonfunctional
e.g.☆alendronate

pharmacology musculoskeletal