Drug vulnerability of peripheral blood platelets.

The effect of antiinflammatory drugs (aspirin, Voltaren), cytotoxic drugs (cyclophosphamide, vincristine), antibiotics (penicillin, chloramphenicol), as well as of dipyridamole on the different ultrastructural and metabolic parameters of human platelets was examined in vitro. Almost all drugs caused a decreased platelet aggregation but of different degrees. The alteration of the internal structure consisted of a decrease in the number of platelet granules, displacement of the granules and mitochondrial damage. The surface alterations affected the number and appearance of platelet pseudopodia. With the exception of Voltaren the drugs exerted an inhibitory effect on platelet protein synthesizing capacity and on their phagocytotic ability. Voltaren stimulated the ability of platelets to engulf latex particles.