Cocaine activates platelets and increases the fomation of circulating platelet containing microaggregates in humans
Even occasional use of cocaine promotes the formation of blood clots, shows a study in Heart. This could explain why the risk of heart attacks is so much higher in people who use the drug, the research concludes.
The heart rates and blood chemical responses were monitored in fourteen 23 to 41 year olds up to two hours after having been given 2 mg per kg of body weight of cocaine, equivalent to recreational use and the same amount of a placebo. None of the volunteers had ever used cocaine before.
Compared with the placebo, cocaine slightly increased heart rate and blood pressure. But chemicals which indicate that the blood is "stickier" and which enhance the formation of clots (thrombosis) had significantly increased two hours after cocaine had been taken. And the bleeding time, a measure of how long it takes the blood to form a clot around a wound, had fallen in two thirds of the volunteers.
Bleeding of the linings of the nose and stomach is a frequent side-effect of snorting coke, say the authors, a factor which is not usually associated with thickening of the blood. But they say, cocaine has a systemic effect that has nothing to do with when or how the drug is taken. And it sets off a chain of events in the blood that promote clots, making the user susceptible to heart attacks.
"The data...add to mounting evidence disproving the widely held belief that occasional cocaine abuse poses little risk. The risk of thrombosis, similar to the risk of sudden cardiac death, is real and may affect even the first time user of small quantities of the drug."