Sorting Out the Different Types of Drug Treatment

Looking at Bisphosphonates for Building Up Bone
Bones are like a bank; your bone “balance” stays healthy as long as you’re not taking out more than you put in. That analogy may be a little simplistic (see Chapter 2 for the more involved detail of bone buildup and breakdown) but in essence, bone strength depends upon the balance between the bone cells that build bone versus those cells that break down bone.

Bisphosphonates are a type of antiresorptive drug that inhibits bone removal by the osteoclasts (see Chapter 2 for more on osteoclasts). Taking bisphosphonates can increase bone density in both the hip (by 3 percent) and lumbar spine (by 5 percent). Changes in bone density can be seen in the first year of treatment. Fracture rates are reduced by 50 percent.

Using alendronate, ibandronate, and risedronate
The most commonly used antiresorptive drugs belong to a class of compounds referred to as bisphosphonates, also called diphosphonates. Three oral bisphosphonates are approved in the United States for both prevention and treatment of osteoporosis:
 Alendronate (Fosamax)
 Ibandronate (Boniva) (the newest drug, it may be difficult to find)
 Risedronate (Actonel)

You may hear alendronate, ibandronate, and risedronate called “diphosphonates” instead of “bisphosphonates.” A diphosphonate is the same thing as a bisphosphonate; just chalk it up to the idiosyncrasies of the scientific world to have two words (long ones, at that) for the same thing. The prefix bis- and di- both refer to the word “two.” These drugs contain two phosphonate groups attached to one carbon atom. This particular structure is responsible for the strong binding of the drug to osteoclasts.