POPULATION VARIABILITY IN THE EFFECT OF ASPIRIN ON PLATELET-FUNCTION - IMPLICATIONS FOR CLINICAL-TRIALS AND THERAPY

Little or nothing is known about how the inhibitory effect of aspirin on platelets distributes in the general population. We describe a simp le whole-blood assay for the extent of aspirin-induced inhibition of p latelet aggregation-and its application to 31 aspirin-treated subjects . Platelet inhibition to two or more 325-mg aspirin tablets was measur ed using a newly developed method in 31 healthy, young adults. These s ubjects showed a wide range of variation in their response to aspirin, which in subsequent studies was found to be stable over time. The eff ect persisted even when the steps of got absorption and liver metaboli sm were bypassed. We conclude that the response of platelets to aspiri n varies to the. extent that a significant proportion of the populatio n may be nonresponsive and that this variability may be intrinsic to p latelets and/or their blood environment.