Can Fosamax (alendronate) be used in patients with impaired renal function post kidney transplant?

From the Guidelines

Fosamax (alendronate) should be used with caution in patients with impaired renal function post kidney transplant, as its use in this population has not been adequately studied, and severe renal impairment is a contraindication 1. When considering the use of Fosamax in post-kidney transplant patients, it is essential to weigh the potential benefits of increased bone mass and reduced fracture risk against the potential risks associated with impaired renal function.

Key Considerations

• The patient's kidney function should be assessed before starting Fosamax, and severe renal impairment (creatinine clearance less than 35 mL/min) is a contraindication 1.
• Regular monitoring of bone mineral density, calcium, vitamin D levels, and kidney function is crucial during treatment.
• Supplemental calcium and vitamin D are typically recommended alongside Fosamax unless contraindicated.
• The medication works by inhibiting osteoclast-mediated bone resorption, helping to maintain or increase bone density that is often compromised by immunosuppressive regimens post-transplant.

Alternative Therapies

• Other bisphosphonates, such as pamidronate, have shown promise in preventing bone mineral density loss in transplant patients 1.
• Calcitonin, a naturally occurring hormone, has also been shown to protect bone mass in conventional osteoporosis and may be considered as an alternative therapy 1.

Dosage and Administration

• The typical dosage of Fosamax is 70 mg once weekly or 10 mg daily, taken with a full glass of water at least 30 minutes before the first food or drink of the day.
• Patients must remain upright for at least 30 minutes after taking it to prevent esophageal irritation. It is crucial to carefully evaluate the risks and benefits of Fosamax in patients with impaired renal function post kidney transplant and to consider alternative therapies and close monitoring to minimize potential adverse effects 1.

From the FDA Drug Label

Renal Impairment: Preclinical studies show that, in rats with kidney failure, increasing amounts of drug are present in plasma, kidney, spleen, and tibia In healthy controls, drug that is not deposited in bone is rapidly excreted in the urine. No evidence of saturation of bone uptake was found after 3 weeks dosing with cumulative intravenous doses of 35 mg/kg in young male rats Although no formal renal impairment pharmacokinetic study has been conducted in patients, it is likely that, as in animals, elimination of alendronate via the kidney will be reduced in patients with impaired renal function. Therefore, somewhat greater accumulation of alendronate in bone might be expected in patients with impaired renal function No dosage adjustment is necessary for patients with creatinine clearance 35 to 60 mL/min. 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

Fosamax (alendronate) use in patients with impaired renal function post kidney transplant is not explicitly recommended or contraindicated. However, the label states that alendronate sodium is not recommended for patients with creatinine clearance less than 35 mL/min.

• The label does not provide specific guidance for patients with impaired renal function post kidney transplant.
• Caution is advised when considering the use of Fosamax in patients with impaired renal function, as reduced elimination of alendronate via the kidney may lead to greater accumulation of alendronate in bone 2.

From the Research

Use of Fosamax in Patients with Impaired Renal Function Post Kidney Transplant

• Fosamax (alendronate) can be used in patients with impaired renal function post kidney transplant, as it has been shown to improve bone mineral density (BMD) in these patients 3.
• A study published in 2012 found that Fosamax increased BMD at the lumbar spine and hipbone in male renal transplant patients, and at the lumbar spine in female patients 3.
• However, it is essential to consider the patient's renal function and potential interactions with other medications, such as immunosuppressive agents, when using Fosamax in this population.
• Another study published in 2018 found that denosumab, a monoclonal antibody, can be a viable therapeutic option for transplanted patients with osteoporosis, especially in those with renal function impairment or bisphosphonate intolerance 4.

Renal Function and Bone Mineral Density

• Impaired kidney function is common in kidney-transplanted patients, and complications of chronic kidney disease (CKD), such as mineral and bone disorders (MBD), are also prevalent in this population 5.
• A study published in 2009 found that serum phosphorus showed a strong negative correlation with graft function in CKD stages 4-5, and hyperphosphatemia was independently associated with the time spent on dialysis before transplantation 5.
• Bone mineral disease after kidney transplantation is a mix of pre-existing disorders and new alterations, and the final consequences are reflected fundamentally as abnormal mineral metabolism and bone alterations 6.

Treatment Options for Osteoporosis in Renal Transplant Patients

• The recommended osteoporosis therapy for organ recipients involves supplementation with calcium and vitamin D and bisphosphonate administration 4.
• However, these options can prove limited for patients with impaired renal function, and alternative therapies such as denosumab may be considered 4.
• Vitamin D supplementation has been found to have beneficial effects on bone health and reduced risk of chronic allograft nephropathy and cancer in renal transplant patients 7.