Proquazone (Sandoz 43-715),An Unusually Potent Inhibitor of the Platelet Release Reaction and Malondialdehyde Formation 1

Summary

Although proquazone is not an acid, its action on platelets is similar to that of a typical acidic NSAID: It inhibits the release reaction and associated production of MDA without affecting primary aggregation caused by ADP or epinephrine, and it fails to inhibit the collagen-induced release which remains after maximal inhibition by aspirin. It is unusually active; it may have an effect in vitro at 11 nM, and is at least 50 times more active than indometha-cin (4) in preventing collagen-induced release from human platelets.

Thanks are due to Kathy Slavin and Sook-Ja Kim for their able technical assistance, and to Robert A. Grant, M.S., for his helpful comments.