Bleeding Times and Platelet Aggregation After Analgesics in Hemophilia

The effect of aspirin, acetaminophen, propoxyphene, and placebo on the Ivy bleeding time, platelet aggregation, and platelet factor 3 availability was evaluated in a double-blind study of severe hemophilia. Acetaminophen and propoxyphene did not prolong the bleeding time and did not affect platelet function in vitro. These drugs can be used safely in severe hemophilia and probably also in other hemorrhagic disorders. Aspirin lengthened the bleeding time in all subjects, although the degree of prolongation varied in individual tests. Differences in the response of the bleeding time to aspirin could not be related to the results of in vitro platelet function tests. Apparently, bleeding times will have to be measured to determine whether a drug that interferes with platelet function in vitro will also interfere significantly with the formation of hemostatic plugs in vivo in the hemophilic patient.