Abstract
Antiplatelet therapy has been shown to play an important role in the prevention of TIA, cerebral thrombosis and ischemic heart diseases. Evaluation of platelet function appears to be important in determining the efficacy of antiplatelet drugs. We recently studied some aggregation inducers and their optimum concentrations, to apply them to evaluation of the major antiplatelet agents, aspirin and ticlopidine.
The subjects consisted of 52 patients with cerebral thrombosis, comprising 20 patients on aspirin therapy (81mg/day) and 32 on ticlopidine therapy (12 on 100mg and 20 on 200mg/day). Turbidimetry was used for the measurement of platelet function.
Results were as follows : 1) To evaluate the efficacy of aspirin, the 2 μg/ml collageninduced maximum or 5 -min aggregation rate appeared to be useful. The 2μM ADPinduced maximum aggregation rate was useful for evaluation of ticlopidine ; 2) A maximum aggregation rate of ≤60% proved to be an appropriate therapeutic range ; 3) The percent maximum aggregation is generally more useful, since it takes less time to determine than 5-min aggregation.
When antiplatelet therapy fails to sufficiently inhibit platelet function, noncompliance, underdosing, and abnormalities of drug absorption and metabolism shoud be considered.
