[Use of bisphosphonates in chronic kidney disease].

Bisphosphonates are synthetic compounds similar to organic pyrophosphates. The bioavailability of intravenous preparations is 100%, whereas the availability of oral therapy ranges from 1 to 5%. About 50% to 80% of free bisphosphonates are incorporated into bone. Because of their urinary elimination, bisphosphonates must be carefully administered in chronic kidney disease (CKD) patients. In spite of this, bisphosphonates can safely be used in all CKD stages, including dialysis and kidney transplant. The renal toxicity seems different among these compounds, and it is due basically to their protein binding and the average lifespan in renal tissues. In practice, renal toxicity have been associate to the infusion velocity and excessive dosage In patients with CKD, it is very relevant to maintain the time of infusion and in haemodialysis patients we recommend the administration during the haemodialysis session. When bisphosphonates are given to 4-5 CKD patients it seems reasonable to reduce the dose to 50%. No renal pathology has been associated to oral administration. The indications of bisphosphonates in CKD include: hypercalcemia episodes, prevention of bone loss after renal transplantation, treatment of low bone mineral density in all CKD stage including transplantation. They are too a promising therapy of calciphylaxis and to prevent vascular calcifications. When suppressed bone turnover is suspected, bone biopsy is mandatory before bisphosphonates therapy.