Renal Function and Tubular Phosphate Handling in Long-Term Cyclosporine- and Tacrolimus-Based Immunosuppression in Kidney Transplantation

Electrolyte Imbalances in Pediatric Living Related Small Bowel Transplantation

“…FK 506 and other calcineurin inhibitors are known to interfere with phosphorus reabsorption, leading to bone loss, which, among other mechanisms, contributes to bone loss after solid organ transplantation, even though FK 506 has been found to be less destructive on bone mass (15). Falkiewicz et al showed FK 506 to interfere with phosphorus homeostasis much less than cyclosporine, even preserving normal range tubular phosphate reabsorption (16); however, our own findings suggest FK 506 as contributor to urinary phosphate losses. Calcium on the other hand showed only a lesser degree of association with FK 506 exposure.…”

Tertiary ‘Hyperphosphatoninism’ Accentuates Hypophosphatemia and Suppresses Calcitriol Levels in Renal Transplant Recipients

“…Increased expression of FGF‐23 mRNA in human osteoblasts has recently been demonstrated in response to dexamethason (21) and nonglucocorticoidal immunosuppressants like tacrolimus, cyclosporine A and sirolimus have recently been shown to affect the expression of bone tissue‐specific genes of human osteoblasts (24). Several clinical studies have linked the use of glucorticosteroids, rapamycine and cyclosporine to hypophosphatemia and prolonged urinary phosphate leak (25–28). The absence of clinically relevant hypophosphatemia following nonrenal organ transplantations despite similar immunosuppressive protocols, however, indicates that immunosuppressive drugs are unlikely the primary pathogenic factor in renal transplant recipients.…”

Drug–Vitamin D Interactions

“…One RCT (Class A, neutral quality 134 ) and five time series studies (Class C; one positive quality 135 , one neutral quality 136 , and three negative quality 137–139 ) evaluated the effect of cyclosporine on vitamin D status. None of the studies reported significant differences in 25(OH)D concentrations when comparing the effect of cyclosporine alone or in combination with prednisone.…”

“…One time series study (Class C, negative quality) evaluated the effect of tacrolimus on vitamin D status in individuals who had undergone renal transplantation 139 . Again, 25(OH)D concentrations were not significantly different than those of the healthy control group at any of the study time points.…”