title: The evaluation method for antiplatelet effect of acetylsalicylic acid.
abstract: Reduced platelet aggregation by acetylsalicylic acid administration has been associated with adverse outcomes in patients with thrombotic diseases, thus it is important to determine aspirin resistance in those cases. The antiplatelet effect of acetylsalicylic acid is rarely measured, but it has many problems. The aim of this study was to find the evaluation method for antiplatelet effect after administration of acetylsalicylic acid. We developed a particle counting method based upon laser light scattering, and utilized the platelet aggregation agonists, collagen, at 0.25, 0.5 and 1.0 μg/mL, and adenosine diphosphate (ADP), at 0.5, 1.0 and 2.0 μM, to determine their effective concentrations. Seventeen healthy volunteers were administered acetylsalicylic acid at 162 mg/day, with platelet aggregation determined before and 20 min after administration. In all subjects, the rate of platelet aggregation induced by 1.0 μg/mL of collagen before taking acetylsalicylic acid was the highest value obtained, while 20 min after acetylsalicylic acid administration, aggregation induced by collagen at 1.0 μg/mL was significantly decreased as compared to before administration. As for the other concentrations of collagen and all those of ADP tested, platelet aggregation was either not significantly induced before taking acetylsalicylic acid or the rate of aggregation was not significantly decreased after taking acetylsalicylic acid. Our results indicate that collagen at 1.0 μg/mL is appropriate as a platelet aggregation agonist for evaluating the antiplatelet effect of acetylsalicylic acid. Thus, it is useful that the measurement is performed only once.
authors.affiliation: Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan.
authors.forename: Haruko
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Mastumura
authors.forename: Shinji
authors.initials: S
authors.lastname: Soeda
authors.forename: Yuji
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Watanabe
authors.forename: Emiko
authors.initials: E
authors.lastname: Kashiwakura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Saso
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ikeda
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tokuoka
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Kitagawa
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001241:Aspirin / Q000494:pharmacology*; D003094:Collagen / Q000494:pharmacology; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*
chemical_list: D010975:Platelet Aggregation Inhibitors; D000244:Adenosine Diphosphate; D003094:Collagen; D001241:Aspirin