In healthy volunteers the effect of dipyridamole on serum and urinary caicium and phosphorus levels

Dipyridamole (D) inhibits the platelet aggreagation and adhesion. Additionally, it is used in cardiovaacular diseases due to the vasodilatation effect related with the inhibition of adenosine degradation. In addition to these effects, Dipyridamole increases serum phosphorus (P) levels and decreases urinary P excretion in patients with primary hyperparathyroidism who have low serum P levels and low renal treshold. In this study we investigated the effects of Dipyridamole on the serum and urine P levels in healthy volunteers. Twenty-six healthy volunteers are included into this study, male/female ratio was 15/11. Dipyridamole was given 3 times 75 mg daily and blood and daily urine samples were taken before and at the end of 7 days of the Dipyridamole therapy. At the end of the Dipyridamole therapy there were no changes in hematocrit, hemoglobin, platelet, white blood cell count, platelet function tests including collogen, ristocetin and thrombin, glucose, BUN, creatinine, serum potassium (K), P, parathormone, Vitamin D, creatinine clearance and urinary sodium (Na) and magnesium (Mg). However serum calcium (Ca) level increased from 9,84±0,35 mg/dl to 10,15±0,64 mg/dl, magnesium (Mg) level increased from 2,05±0,13 mg/dl to 2,32±0,52 mg/dl. Serum sodium (Na) level decreased from 142,42±3,31 mmol/l to 138,96±4,69mmol/l. Daily urinary Ca level increased from 100,31±49,09 mg to 134,73±68,98mg. Daily urinary K decreased from 46,24±20,35 mmol to 38,98±12,87 mmol, and tubular phosphorus reabsortion (TPR) decreased from 0,88±0,35 to 0,84±0,56. TmP/GFR decreased from 3,6 ±0,60 mg/dl to 3,3±0,57 mg/dl. In summary, we did not detect decrease of urinary P excretion. in healthy volunteers by using Dipyridamole which increases TPR and TmP/GFR secondary to inhibiton of adenosin re-uptake and/or P glikoprotein activity. In contrast to other studies, we found that Dipyridamole caused a decrease in TPR and TmP/GFR in healthy volunteers. In addition we found increase in serum Ca levels and urinary Ca excretions and decrease in serum Na levels and urinary K levels. For these results we can conclude that Dipyridamole affects the tubular functions and renal P and Ca excretions in healthy volunteers and also effects the serum Na levels. We need similar studies exploring probable mechanisms in larger groups.