Effects of aspirin, dipyridamole, nifedipine and cavinton which act on platelet aggregation induced by different aggregating agents alone and in combination

Abstract

The effects of aspirin, nifedipine, dipyridamole and cavinton on platelet aggregability in patients with atherosclerosis has been studied using various agents to induce aggregation. The drugs reduced platelet aggregability when aggregation was induced by ADP, adrenaline, or collagen alone. However, if platelet aggregation were induced by combinations of the agonists (including combinations of ADP with either adrenaline or platelet-activating factor (PAF), adrenaline with PAF, and collagen with ADP), the anti-aggregant effects of aspirin, dipyridamole, and cavinton were significantly reduced. The effect of nifedipine was less markedly reduced, especially by combinations which included adrenaline. The data suggest that positive agonist interactions may lead to a reduction in the therapeutic activity of antiplatelet drugs.