title: Aspirin and clopidogrel resistance: possible mechanisms and clinical relevance. Part II: Potential causes and laboratory tests.
abstract: Recent meta-analyses have indicated that patients with vascular disease demonstrated by laboratory tests to be aspirin or clopidogrel-resistant are at an increased risk of major vascular events. The suggested mechanisms of aspirin resistance include genetic polymorphism, alternative pathways of platelet activation, aspirin-insensitive thromboxane biosynthesis, drug interactions, or a low aspirin dose. Clopidogrel resistance is likely to develop as a result of a decreased bioavailability of the active metabolite, due to genetic variation or concomitant drug treatment. Additional work is required to improve and validate laboratory tests of platelet function, so that they may become useful tools for selection of the most appropriate antiplatelet therapy for an individual patient. Improvements in antiplatelet treatment strategies in the future should lead to a reduction in premature vascular events.
authors.affiliation: University of Szeged, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, Neurology Department, Szeged, Hungary.
authors.forename: Dávid
authors.initials: D
authors.lastname: Vadász
authors.forename: László K
authors.initials: LK
authors.lastname: Sztriha
authors.forename: Katalin
authors.initials: K
authors.lastname: Sas
authors.forename: László
authors.initials: L
authors.lastname: Vécsei
mesh_terms: D000367:Age Factors; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D001682:Biological Availability; D000077144:Clopidogrel; D004334:Drug Administration Schedule; D004347:Drug Interactions; D004351:Drug Resistance; D006801:Humans; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010979:Platelet Function Tests; D011110:Polymorphism, Genetic; D012737:Sex Factors; D015398:Signal Transduction; D013931:Thromboxanes / Q000096:biosynthesis; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D013931:Thromboxanes; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin