Effects of Drugs on Bone Quality

Abstract

The term bone quality refers to factors that define bone mechanical strength and hence its fracture risk, either inclusive or exclusive of the quantity of mineralized tissue present. These factors include: bone size, density, shape (microarchitecture, geometry, remodeling cavity number size and distribution), porosity, mineral and collagen distribution and alignment, amount and distribution of microdamage, mineral composition, collagen cross-linking and other material properties. In this review, we will consider how pharmaceuticals used to treat osteoporosis (anabolic and catabolic agents) and those used for other conditions that affect bone quality and induce “secondary osteoporosis” alter these parameters. Observed effects vary with different methods of drug delivery, length and periodicity of use, other drugs used concomitantly or consecutively, user gender, methods of analysis and, most importantly, the genetic background of the species tested. We suggest that while increases in quantity of mineralized tissue present account for much of the reported reduction in fracture risk, drugs that correct the composition and microarchitecture of the bone, returning it to its preosteoporotic status, may provide additional benefits.