Alendronate: an update of its use in osteoporosis

Alendronate (alendronic acid) is a nitrogen-containing bisphosphonate which binds to bone surfaces and inhibits bone resorption by osteoclasts. Oral alendronate 5 or 10 mg/day produces sustained increases in bone mineral density (BMD) in postmenopausal women with or without osteoporosis, in men with primary osteoporosis and in both men and women with or without osteoporosis receiving systemic corticosteroid therapy. Histomorphometric analyses have found that alendronate does not appear to impair bone quality. Alendronate reduced the risk of radiographic vertebral fracture, clinical vertebral fracture or hip fracture by 47 to 56% in postmenopausal women who had > or = 1 existing vertebral fracture and in those with no existing vertebral fractures but who had osteoporosis. In a number of comparative trials in postmenopausal women with osteoporosis, alendronate 10 mg/day was found to be more effective at inducing sustained increases in BMD than intranasal calcitonin, and at least as effective as conjugated estrogens and raloxifene. Alendronate 70 mg administered once weekly and 35 mg twice weekly are as effective at increasing BMD as 10 mg/day in this patient group. In clinical trials, alendronate was generally well tolerated when taken as recommended. Adverse events tended to be transient and associated with the upper GI tract, most commonly including abdominal pain, nausea, dyspepsia, acid regurgitation and musculoskeletal pain. No statistically significant differences between alendronate 10 mg/day and placebo have been found in the incidence of upper GI adverse events in large clinical trials. However, postmarketing surveillance reported a low incidence of adverse events related to the oesophagus. Specific instructions aimed at reducing the risk of upper GI adverse events have been provided by the manufacturer.

Alendronate is effective and generally well tolerated in the treatment of women or men with primary (including postmenopausal) or corticosteroid-induced osteoporosis and in the prevention of osteoporosis in postmenopausal women. The drug has been associated with upper GI tract adverse events, although the extent to which alendronate is responsible for these events has not been clearly established. Alendronate should be considered a treatment of choice in postmenopausal women with osteoporosis. Alendronate is also a suitable treatment option for primary osteoporosis in men and for corticosteroid-induced osteoporosis in both men and women.