Effects of cocaine on human platelet aggregation in vitro.
BACKGROUND
A temporal relationship has been established between cocaine ingestion and myocardial infarction, and a cocaine-induced increase in platelet aggregation has been suggested as a possible explanation. However, the mechanisms of cocaine associated coronary thrombosis have yet to be completely elucidated. For this reason, we examined the in vitro effect of cocaine and its metabolites on platelet aggregation.


METHODS
Platelet aggregation was tested by obtaining platelet rich plasma from 42 healthy volunteers and incubating the platelet rich plasma in six concentrations of cocaine (ranging from 1.47 to 2940 nmol) for 10 minutes prior to aggregation with ADP 1 microM. The same procedure was used to test the effect of two cocaine metabolites, benzoylecgonine and ecgonine methyl ester, on platelet aggregation. Abnormal results were confirmed by inducing aggregation with ADP at higher concentrations (2.4 and 10 microM) and with arachidonic acid (624 microM).


RESULTS
At increasing concentrations, cocaine progressively inhibited ADP and arachidonic acid induced platelet aggregation. No effect was seen with benzoyl ecgonine or ecgonine methyl ester as compared to saline.


CONCLUSIONS
These data suggest that under certain conditions cocaine may negatively affect hemostasis by decreasing platelet aggregation.
Heesch
C M
CM
Department of Internal Medicine (Division of Cardiology), University of Texas Southwestern Medical Center, Dallas 75216, USA.
Steiner
M
M
Hernandez
J A
JA
Ashcraft
J
J
Eichhorn
E J
EJ
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology; D003042:Cocaine / Q000031:analogs & derivatives / Q000378:metabolism / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D009294:Narcotics / Q000378:metabolism / Q000633:toxicity*; D010974:Platelet Aggregation / Q000187:drug effects*; D013927:Thrombosis / Q000209:etiology
D009294:Narcotics; C005618:benzoylecgonine; D000244:Adenosine Diphosphate; D003042:Cocaine; C034524:ecgonine methyl ester