Effects of anti-inflammatory drugs on platelet aggregation in rabbits

Effects of non-steroidal anti-inflammatory drugs (aspirin, indimethacin, flufenamic acid, tiaramide and HG-70) on rabbit platelet aggregation were studied using Evans aggoregometer and a modified form of Chandler's loop method. Tiaramide in 10(-4) and 10(-5)M inhibited effectively the aggregation caused by ADP in the optical density method and accelerated the restoration of the time course of disaggregation in the loop method. The other 4 drugs were ineffective. In collagen-induced aggregation all 5 drugs inhibited the aggregation. Among them tiaramide was most potent. Only tiaramide prolonged the time taken to induce snow storm and aggregates in the loop method.