Dipyridamole for renal phosphate leak in successfully renal transplanted hypophosphatemic patients

Hyphosphatemia can be seen in renal transplant recipients. Hyperparathyroidism, glucocorticoid treatment, renal denervation and impairment of renal tubular phosphate reabsorption are the most common causes of hyphosphatemia in these patients. It is well-known that dipyridamole enhances renal tubular phosphate reabsorption in some clinical conditions. We did not find any information about the effect of dipyridamole in renal transplant recipients (RTRs) with hypophosphatemia. For this reason, we decided to give dipyridamole 11 RTRs with hypophosphatemia.

Eleven RTRs whose serum phosphate and creatinine levels were below 2.5 mg/dl and 2 mg/dl, respectively, were included in this study. None of the patients received drugs altering phosphate metabolism and they did not change their routine diets. Urinary phosphate excretion and tubular phosphate reabsorption (TPR) were calculated before and 3 weeks after dipyridamole treatment.

The mean levels of serum-urine (daily) phosphate and TPR before dipyridamole treatment were 1.94 +/- 0.46 mg/dl, 7,187.5 +/- 1,833.49 mg/day and -2.78 +/- 0.62, respectively. After treatment, the mean levels of serum-urine phosphate and TPR were 2.73 +/- 0.46 mg/dl, 4,845.27 +/- 1,138.99 mg/day and -1.48 +/- 0.80, respectively. Serum and urine phosphate levels and TPR were found to be significantly different before and after dipyridamole therapy (p < 0.05).

Short-term dipyridamole therapy increased TPR and serum phosphate levels and decreased urinary phosphate excretion. We did not observe negative effect on renal functions in these cases. Although the number of the cases included in this study is small, dipyridamole is an effective choice in management of hypophosphatemic RTRs.