Role of glucosamine in the treatment for osteoarthritis.

Over the last 20 years, several studies have investigated the ability of glucosamine sulfate to improve the symptoms (pain and function) and to delay the structural progression of osteoarthritis. There is now a large, convergent body of evidence that glucosamine sulfate, given at a daily oral dose of 1,500 mg, is able to significantly reduce the symptoms of osteoarthritis in the lower limbs. This dose of glucosamine sulfate has also been shown, in two independent studies, to prevent the joint space narrowing observed at the femorotibial compartment in patients with mild-to-moderate knee osteoarthritis. This effect also translated into a 50 % reduction in the incidence of osteoarthritis-related surgery of the lower limbs during a 5-year period following the withdrawal of the treatment. Some discrepancies have been described between the results of studies performed with a patent-protected formulation of glucosamine sulfate distributed as a drug and those having used glucosamine preparations purchased from global suppliers, packaged, and sold over-the-counter as nutritional supplements.

Current options for the management of postmenopausal osteoporosis.

INTRODUCTION: Osteoporosis is a well-recognized disease with severe consequences if left untreated. The prevention of osteoporosis-associated fractures should include fall prevention, calcium supplementation and life-style advice, as well as pharmacological therapy using agents with proven antifracture efficacy. AREAS COVERED: This manuscript offers an evidence-based critical assessment of the currently available efficacy data on all new chemical entities that have been granted a marketing authorization for the management of primary osteoporosis in women. EXPERT OPINION: The availability of new therapeutic agents makes clinical decision making in osteoporosis more complex. Therapeutic decisions should be based on a balance between the benefits and risks of treatment, which must be carefully considered in each particular case, both by the physician and the patient. Indeed, no single agent is appropriate for all patients. Therefore, treatment decisions should be made on a tailor-made basis, taking into account all measures of treatment effect and risk, before making informed judgments about the best individual treatment option.

Importance of alfacalcidol in clinical conditions characterized by high rate of bone loss.

In postmenopausal osteoporosis, the administration of alfacalcidol to women resulted in an increase in trabecular bone mineral density (BMD), prevention of cortical bone loss, and a significant reduction in the incidence of further vertebral fractures. There is now robust evidence that alfacalcidol may be particularly active in conditions characterized by an increased rate of bone loss. Alfacalcidol 1 microg/day fully prevented vertebral bone loss over 3 years in women after the first year of menopause. In a large cohort of individuals starting treatment with high dose corticosteroid (CS, 46.6 mg equivalent prednisolone per day), the spinal bone loss observed in untreated patients was fully prevented by administration of 1 microg/day alfacalcidol. In patients with established CS-induced osteoporosis, with or without prevalent vertebral fractures, 1 microg/day of alfacalcidol, given for 3 years, increased lumbar spine density, reduced back pain, and showed a significant reduction in the rate of new vertebral fractures, compared to native vitamin D. In cardiac transplant recipients, alfacalcidol and calcium reduced spinal and femoral bone loss, compared to a control group treated with etidronate and calcium. Alfacalcidol-treated patients experienced fewer new vertebral fractures over the 2-year followup. When alfacalcidol and vitamin D3 were compared in elderly women with radiologic evidence of vertebral fracture, fractional calcium absorption was increased after 3 months with alfacalcidol but was unchanged with vitamin D3. In a recent metaanalysis of 14 studies of native vitamin D and 19 studies of D-hormone analogs (alfacalcidol and calcitriol), the D-analogs exerted a higher preventive effect on bone loss and fracture rates in patients with no exposure to CS. In head-to-head studies comparing D-analogs and native vitamin D in patients receiving CS, this metaanalysis identified significant effects favoring D-analogs for femoral neck BMD and spinal fractures. In conclusion, improvement in bone turnover, increase in BMD, and reduction in fracture rates have been described during alfacalcidol treatment in situations characterized by a high rate of bone loss, including CS-induced osteoporosis, early postmenopausal bone loss, and organ transplant. Compared to plain vitamin D, alfacalcidol exerts higher bone-protective effects, thus allowing the doses to be minimized and lowering the risk of adverse effects, including hypercalcemia.