What is the comparison between Risedronate (Bisphosphonate) and Alendronate (Bisphosphonate)?

From the Guidelines

Both risedronate and alendronate are effective bisphosphonates for treating osteoporosis, with high-quality evidence supporting their use in reducing the risk of vertebral, nonvertebral, and hip fractures in postmenopausal women with osteoporosis, as recommended by the American College of Physicians 1, 2. When comparing the two, alendronate is typically considered first-line due to its extensive evidence base and lower cost as a generic medication, usually prescribed at 70mg once weekly or 10mg daily. Risedronate, on the other hand, has a slightly faster onset of action and may cause less esophageal irritation, making it preferable for patients with upper GI sensitivity, with a typical dose of 35mg once weekly or 150mg once monthly. Some key points to consider when choosing between these medications include:

• Cost considerations: Alendronate is generally less expensive as a generic medication.
• Patient tolerance: Risedronate may be preferred for patients with upper GI sensitivity due to its potentially lower risk of esophageal irritation.
• Adherence factors: Both medications require similar administration, including taking on an empty stomach with a full glass of water and remaining upright for 30-60 minutes afterward. Both drugs effectively reduce fracture risk by inhibiting bone resorption, with fracture reduction benefits appearing within 6-12 months of treatment, as supported by high-quality evidence from studies such as those cited in the American College of Physicians guideline update 1, 2. If a patient experiences GI side effects with alendronate, switching to risedronate is a reasonable option before considering non-bisphosphonate alternatives, as both medications have been shown to be effective in reducing fracture risk in postmenopausal women with osteoporosis 1, 2. It's also important to note that both bisphosphonates and denosumab are associated with mild gastrointestinal symptoms, and bisphosphonates are associated with atypical subtrochanteric fractures and osteonecrosis of the jaw, as reported in the American College of Physicians guideline update 2. When prescribing bisphosphonates, clinicians should discuss the importance of adherence, as factors such as side effects and the inconvenience of taking medications can impact patient adherence, as noted in the guideline update 2. Overall, the choice between risedronate and alendronate should be based on individual patient factors, including cost considerations, patient tolerance, and adherence factors, with the goal of reducing fracture risk and improving outcomes for patients with osteoporosis, as supported by high-quality evidence from studies such as those cited in the American College of Physicians guideline update 1, 2.

From the FDA Drug Label

12. 1 Mechanism of Action Animal studies have indicated the following mode of action. At the cellular level, alendronate shows preferential localization to sites of bone resorption, specifically under osteoclasts.

12. 2 Pharmacodynamics Alendronate is a bisphosphonate that binds to bone hydroxyapatite and specifically inhibits the activity of osteoclasts, the bone-resorbing cells. INDICATIONS AND USAGE Risedronate sodium is a bisphosphonate in a delayed-release formulation and is indicated for treatment of postmenopausal osteoporosis (1.1)

Both Alendronate and Risedronate are bisphosphonates.

• They both work by inhibiting osteoclast activity, which are the bone-resorbing cells.
• The main difference between the two is their formulation, with Risedronate being in a delayed-release formulation.
• There is no direct comparison of their efficacy or safety in the provided drug labels [3] [4].

From the Research

Comparison of Risedronate and Alendronate

• Both risedronate and alendronate are bisphosphonates that are effective in treating and preventing osteoporosis, increasing bone mass, and reducing the risk of vertebral and nonvertebral fractures 5, 6.
• Studies have shown that alendronate and risedronate are the most well-studied bisphosphonates in terms of efficacy and safety, and are approved by the US FDA for the prevention of bone loss in recently menopausal women, treatment of postmenopausal osteoporosis, and management of glucocorticoid-induced bone loss 5.
• A systematic review with network meta-analyses found that zoledronic acid seemed to be the most effective in preventing vertebral fracture, nonvertebral fracture, and any fracture, while alendronate or zoledronic acid seemed to be the most effective in preventing hip fracture 7.
• Another study found that risedronate ranked best in preventing non-vertebral fracture in both primary osteoporosis and corticosteroid-induced osteoporosis, while zoledronic acid ranked as the most effective in preventing vertebral fracture in primary osteoporosis 8.
• An observational study found that patients receiving risedronate had lower rates of hip and nonvertebral fractures during their first year of therapy than patients receiving alendronate, with an 18% lower incidence of nonvertebral fractures and a 43% lower incidence of hip fractures 9.

Efficacy in Preventing Fractures

• Both risedronate and alendronate have been shown to reduce the risk of vertebral and nonvertebral fractures in women with postmenopausal osteoporosis 6.
• Risedronate has been found to be effective in preventing non-vertebral fracture in men with primary osteoporosis and corticosteroid-induced osteoporosis 8.
• Alendronate has been found to be effective in preventing hip fracture, and is one of the most effective bisphosphonates in preventing any fracture 7.

Safety and Tolerability

• Both risedronate and alendronate are generally safe and well-tolerated, with similar adverse event profiles 5, 6.
• The most common adverse events associated with bisphosphonates include gastrointestinal symptoms, such as nausea, vomiting, and diarrhea, as well as musculoskeletal pain and headache 5, 6.