Alendronate and Risedronate for the Treatment of Postmenopausal Osteoporosis: Clinical Profiles of the Once-Weekly and Once-Daily Dosing Formulations

Ronald Emkey, MD


Medscape General Medicine. 2004;6(3):6 

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Once a patient has been identified to be at risk of fracture, the most important therapeutic goal is to reduce this risk as quickly as possible. The bisphosphonates alendronate and risedronate have consistently been shown to be effective therapies for the prevention and treatment of osteoporosis.[58] Both alendronate and risedronate have consistently reduced the risk of morphometric vertebral fractures in patients treated for at least 3 years, and prospective risedronate trials demonstrated reductions in morphometric vertebral fracture risk as early as 1 year. Reductions in clinical vertebral fractures were observed after 1 year of treatment with alendronate and risedronate. Significant reductions in nonvertebral fractures with both bisphosphonates were also seen after 1 year of treatment.

Less frequent administration of a chronic medication may improve patient compliance (as shown by fluoxetine).[59] For some women, long-term compliance with treatment for postmenopausal osteoporosis may be more convenient with a once-weekly dosage regimen. The tolerability profiles of once-weekly bisphosphonate regimens are similar to the once-daily.[40,41,43] Risedronate once daily is well-tolerated in women with postmenopausal osteoporosis, including those at increased risk of upper gastrointestinal adverse events due to preexisting upper gastrointestinal disease or the concomitant use of potentially ulcerogenic agents. In a head-to-head trial of the 2 bisphosphonates, alendronate 10 mg/day was associated with a higher incidence of gastric and esophageal ulcers than risedronate 5 mg/day.[55] EGD scores were also higher. However, in a second study, with a higher dose of both bisphosphonates and longer duration of treatment, endoscopic gastric ulcers were similar in both bisphosphonate treatment groups.

In conclusion, once-weekly administration of alendronate or risedronate provides efficacy (increasing BMD and decreasing markers of bone turnover) and safety similar to once-daily administration in the treatment of postmenopausal women with osteoporosis. Because of the differences in trial protocols and the paucity of head-to-head comparisons between these bisphosphonates, clinicians should be aware of the data available for both bisphosphonates when considering a treatment option.