The Effects of Parathyroid Hormone and Alendronate Alone or in Combination in Postmenopausal Osteoporosis

Theoretically, concomitant therapy with parathyroid hormone and alendronate might be synergistic, increasing bone formation while simultaneously reducing resorption. In this study, 238 postmenopausal women with osteoporosis were randomly assigned to receive daily parathyroid hormone (1–84), alendronate, or both for 12 months. Bone mineral density increased in all groups, with no significant differences between those receiving parathyroid hormone and those receiving both drugs. Bone formation increased markedly with parathyroid hormone therapy but not with combined therapy. No evidence of synergy with PTH plus alendronate. The prevention of osteoporotic fractures with the use of antiresorptive drugs represents an established therapeutic approach for patients with osteoporosis. 1 – 3 The results of double-blind, randomized, placebo-controlled trials have indicated that nitrogen-containing bisphosphonates such as alendronate and risedronate, which work principally by suppressing bone resorption, reduce the risk of fracture and increase bone mineral density. 4 – 8 Unlike bisphosphonates, parathyroid hormone is anabolic when it is administered intermittently for osteoporosis. Both parathyroid hormone (1–34) and parathyroid hormone (1–84) increase bone density by stimulating bone formation rather than by reducing bone resorption. 9 – 12 Recently, the 34-amino-acid fragment, parathyroid hormone (1–34), was shown . . .