Table 1.

Pathophysiological rationale for use in the prevention and/or treatment of GIOP

Therapeutic agents	Rationale for use in GIOP	Proposed mechanism of action
Calcium, vitamin D and analogues	Decreased calcium absorption in the gut	Counter GC-induced secondary hyperparathyroidism
	Increased urinary elimination of calcium
Bisphosphonates	Increased lifespan of osteoclasts	Specific inhibition of bone resorption
	Decreased lifespan of osteoblasts and osteocytes	Reverse the increased osteoblast and osteocyte apoptosis
Calcitonin	Early increase in bone resorption	Specific inhibitor of osteoclast function
Parathormone (intermittent teriparatide)	Increased osteoblast apoptosis	Increases the lifespan of osteoblasts
Fluoride	Increased osteoblast apoptosis	Potent osteoblast mitogen
Androgens/estrogens (opposed or unopposed)	Decreased sex hormone levels through inhibition of gonadotropin secretion and impairment of androgen production	Increase levels of circulating testosterone/estrogen