[Pharmacodynamic approach to the optimal use of calcium antagonists in patients with cerebrovascular disorders]

Three hours after administration of a single 20 mg dose of nifedipine the platelet, leucocyte and red blood cells aggregation was inhibited with the red blood cells and leucocytes deformability increased. This effect proved sensitive to the plasma nifedipine concentration disappearing with its concentrations below 25 ng/ml. The nifedipine sensitivity of the blood cells was the second factor influencing its effect. This was closely related to prostacyclin. The blood cells sensitivity to the latter, and its plasma concentration and decay rates were major determinants of the nifedipine capability of inhibiting the leucocyte, red blood cells and especially platelet inhibition.