Nonreceptor interactions in the pharmacology of blood platelets.

: On the basis of values corresponding to concentrations exhibiting 50% inhibition of platelet aggregation induced with different stimuli and 50% inhibition of arachidonic acid liberation and thromboxane generation, we compared the antiplatelet effect of two cationic amphiphilic drugs--chloroquine and dithiaden. Compared to chloroquine, dithiaden was much more effective in inhibiting platelet aggregation, A-23187 induced arachidonic acid liberation and thromboxane generation. Chloroquine, on the other hand, was more effective in the inhibition of thrombin-induced arachidonic acid liberation.