mechanisms underlying this potential relative resistance to post-teriparatide bone loss in men are unclear. This observation requires confirmation in larger studies and in men and women receiving the approved teriparatide dose of 20 mcg/day. One concern is that teriparatide appears to require continued administration for a sustained biological effect, unlike bisphosphonates that have persistent effects on bone resorption many months after drug exposure ,  and . However, Lindsay et al. also reported that women with postmenopausal osteoporosis showed sustained vertebral fracture risk reduction after withdrawal of teriparatide (at least 18 months) . Finally, a post-marketing study on the use of teriparatide in the US, derived this website from the Direct Assessment of Nonvertebral Fracture in the Community Experience (DANCE) study, described gender differences for initiating teriparatide therapy. The drug was used more often in women, based
on general frailty, low body mass and an inadequate response or intolerance to previous therapy. Chronic glucocorticoid therapy was the reason most often given by investigators for initiating therapy in men, and more often used as an indicator for therapy in men, illustrating the possibility that at least in the US, physicians view teriparatide use somewhat differently in men vs. women , and providing further evidence from a clinical practice setting that male osteoporosis is under-diagnosed and likely under-treated. A study randomly assigned 83 men with low BMD to receive 10 mg/day alendronate, 40 mcg/day teriparatide subcutaneously, or both. Alendronate was administered for 30 months, Selleckchem GW-572016 and teriparatide was started after six months. Lumbar spine and femoral neck BMD increased significantly more in men on teriparatide monotherapy compared with the other groups. Changes in serum BTM were significantly greater in the teriparatide group than in the alendronate group or
the combination therapy group (p < 0.001). As with BMD, a second study showed that alendronate impaired the action of teriparatide to increase bone turnover in men  and . Previous studies in postmenopausal women also suggested that concomitant alendronate those and PTH (1–84) reduced the anabolic effects of PTH  and . These data may influence therapeutic choices after PTH discontinuation, because its use is limited to a maximum of two years . Although these studies suggested that combination of teriparatide and bisphosphonates had no additive effect because alendronate diminished the teriparatide effect, zoledronic acid was shown not to block the anabolic effect of PTH. In a one-year partial double-blind randomised study of 412 postmenopausal women, Cosman et al. concluded that, while teriparatide increased spine BMD more than zoledronic acid, and zoledronic acid increased hip BMD more than teriparatide, combination therapy provided the best BMD improvement, both in spine and hip BMD .