Resistance to aspirin and clopidogrel therapy.
BACKGROUND
Despite increasing evidence on the roles of aspirin and clopidogrel in decreasing morbidity and mortality from cardiovascular disease, resistance to therapy remains an emerging clinical entity. The aim of this review was to revisit current knowledge of the mechanisms, laboratory evaluation, clinical impact and management of resistance to aspirin and clopidogrel therapy.


METHODS
Potentially relevant studies were identified from an electronic search of MEDLINE and PubMed databases. There were no language or publication year restrictions. References in published articles were also reviewed.


RESULTS
Several definitions for resistance have been set, and various laboratory testing modalities are available. The pathophysiological mechanisms remain poorly understood; yet, several extrinsic, intrinsic and genetic factors are described. The clinical implications of this phenomenon are alarming and warrant concern. Management is currently limited to dosing alteration and introduction of other antiplatelet agents.


CONCLUSIONS
Data from ongoing and future studies are awaited to better understand this entity and to highlight the most appropriate treatment strategies.
Department of Internal Medicine, American University of Beirut Medical Center, Riad El Solh 1107-2020, Beirut, Lebanon.
K M
KM
Musallam
K
K
Charafeddine
A
A
Bitar
M
M
Khoury
S
S
Assaad
J
J
Beresian
S
S
Alam
A T
AT
Taher
D001241:Aspirin / Q000494:pharmacology / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000188:drug therapy*; D000077144:Clopidogrel; D004351:Drug Resistance; D006801:Humans; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin