From the FDA Drug Label
alendronate sodium is not recommended for patients with creatinine clearance less than 35 mL/min due to lack of experience with alendronate in renal failure
The recommended Glomerular Filtration Rate (GFR) for Fosamax (Alendronate) administration is a creatinine clearance of 35 mL/min or greater 1.
From the Research
Fosamax (alendronate) can be administered to patients with a Glomerular Filtration Rate (GFR) of 45 mL/min/1.73 m2 or higher, as evidenced by the most recent study 2. For patients with a GFR greater than 45 mL/min/1.73 m2, the standard dose of Fosamax can be used: 70 mg once weekly for osteoporosis treatment or 10 mg daily. However, for patients with a GFR below 45 mL/min/1.73 m2, the use of Fosamax should be approached with caution due to the potential risk of drug accumulation and lack of adequate studies in this population. This recommendation exists because bisphosphonates like Fosamax are primarily eliminated by the kidneys, and impaired kidney function can lead to higher drug concentrations in the body, potentially increasing the risk of adverse effects. Some studies suggest that the incidence of vertebral fractures on alendronate was constant regardless of renal function 2, while others indicate that alendronate can be effective in improving bone mineral density and reducing fracture risk in patients with moderate reductions in GFR 3. For patients with severe kidney impairment, alternative osteoporosis treatments such as denosumab (Prolia) may be more appropriate as they don't rely on kidney clearance. Always ensure kidney function is assessed before starting Fosamax therapy and periodically during treatment, especially in elderly patients or those with conditions that might affect kidney function. Key considerations for Fosamax administration include:
- Patient kidney function, as measured by GFR
- Potential risk of drug accumulation in patients with impaired kidney function
- Alternative treatment options, such as denosumab, for patients with severe kidney impairment
- Regular monitoring of kidney function during Fosamax treatment.