Dipyridamole Can Augment the Resistance to Parathormone in Chronic Renal Failure

Dipyridamole which is used for vasodilatation might enhance renal tubular reabsorption of phosphate. In this study, we aimed to investigate the effect of dipyridamole on Ca, P metabolism, PTH, renal functions and electrolytes in pre-dialysis patients with stable renal function. Thirty pre-dialysis patients with stable renal function were treated with dipyridamole for 4 weeks without their treatment and diet being changed. Baseline (I) serum levels of BUN, creatinine, sodium, potassium, chlorur, Ca, P, magnesium, PTH, Vitamin D3, creatinine clearance and urinary BUN, Cr, Na, FENa, Ca, P, total phosphate reabsorption were measured. These parameters were repeated at the end of the therapy (II) and 4 weeks after withdrawal of dipyridamole (III). There was no difference for all parameters for 3 measurements, except PTH. The mean values of PTH for I, II and III measurements were 152.2±124.1, 230.7±196.6, 210.9±163.2 pg/mL, respectively. The differences between I-II and I-III for PTH were significant (p<0.05). But, the difference between II and III was not significant. Consequently, dipyridamole increased serum PTH levels without any effect on renal functions, serum Ca-P and Vitamin D3 levels and this effect continued for 4 weeks after withdrawal of dipyridamole in pre-dialysis patients . But, this effect of dipyridamole on PTH should be investigated in patients with secondary hyperparathyroidism and we recommend being cautious in using of dipyridamole in predialysis patients.