title: In vitro and ex vivo effects of aspirin in patients on a low-dose aspirin therapy.
abstract: In 19 patients on a low-dose aspirin therapy with 100 mg/d, an insufficient effect of aspirin was observed in five patients (aggregations induced by arachidonic acid and collagen, thromboxane B2-formation in serum and after collagen). Aspirin added in vitro increased the inhibition to a degree comparable to that seen in the other 14 patients, i.e. the insufficient effect could be due to a lack of compliance or to a reduced availability of the drug. In another 20 patients there was a good inhibitory effect of aspirin; additional aspirin did not increase the inhibition of arachidonic acid-induced aggregation and serum-thromboxane B2, but slightly increased collagen-induced aggregation and thromboxane B2 formation. The effect was the same, whether the aspirin was given in vivo or added in vitro.
authors.affiliation: Department of Internal Medicine, Justus-Liebig-University, Giessen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Voss
authors.forename: B S
authors.initials: BS
authors.lastname: Geissler
authors.forename: H
authors.initials: H
authors.lastname: Tillmanns
authors.forename: F R
authors.initials: FR
authors.lastname: Matthias
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016718:Arachidonic Acid / Q000494:pharmacology; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D003094:Collagen / Q000494:pharmacology; D003327:Coronary Disease / Q000097:blood / Q000188:drug therapy; D006801:Humans; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D013929:Thromboxane B2 / Q000096:biosynthesis
chemical_list: D016718:Arachidonic Acid; D013929:Thromboxane B2; D003094:Collagen; D001241:Aspirin