How Cocaine Affects the Cardiovascular System

Cocaine, one of the most commonly used illegal drugs, can produce several kinds of toxic effects on the human body. Among the most dangerous of these are the cardiovascular effects.

In fact, there are few things emergency room doctors dread more than seeing a young cocaine user showing up with chest pain, or other symptoms suggestive of cardiovascular disease. Their dread is well-founded.

Cocaine use can produce a variety of potentially catastrophic cardiovascular problems, which may be entirely acute or may become chronic. Worse, these problems may occur even in people whose cocaine exposure is limited to occasional, recreational usage.

So the dread is understandable. What the ER doctor sees is a young, otherwise-healthy person who may be suffering from a cocaine-induced life-threatening or disability-producing cardiac condition. Worse, the doctor knows that even if a correct diagnosis is made rapidly and treatment is instituted right away, this young person’s long-term outcome is all too likely to remain poor, because of the widespread effects of cocaine on human physiology.

Cocaine is a drug that inhibits the reuptake of norepinephrine in neurons throughout the body. Norepinephrine is a powerful neurotransmitter within the sympathetic nervous system, and when its reuptake is inhibited, the sympathetic nervous activity becomes greatly exaggerated and prolonged. 

The exaggerated sympathetic nervous activity has profound effects on the cardiovascular system. It substantially increases the force of the heart muscle as it contracts, and at the same time, it raises the heart rate and the blood pressure. These factors all greatly increase the work of the heart, and therefore the demand of the heart for oxygen and nutrients.

But at the same time that it is causing the cardiovascular system to work so much harder, cocaine simultaneously limits the amount of work the heart can do without damaging itself. It does this by causing constriction of the capillaries, thus reducing the blood flow to the heart muscle. In addition, cocaine promotes blood clotting within blood vessels, which limits blood flow to vital organs — including the heart.

Several important cardiovascular conditions can result from this combination of effects caused by cocaine use.

Myocardial infarction (heart attack). Heart attacks are a well-known complication of cocaine use, and can occur with any dose of cocaine, and even in first-time users. Most cocaine-induced heart attacks occur within one hour of using the drug, and they are particularly prevalent in younger people. In fact, cocaine use has been implicated in nearly 25% of heart attacks that occur in people under 45. 

Aortic dissection Acute aortic dissection — a sudden tearing of the wall of the aorta — is an extremely painful and life-threatening condition. While there are many causes of aortic dissection, in young people cocaine use is a prevalent cause.

Coronary artery aneurysm. Coronary artery aneurysms, balloon-like dilations of coronary arteries, are fairly common in cocaine users, occurring in about 30% of chronic users. Coronary artery aneurysms are a cause of heart attack.

Myocarditis and cardiomyopathy. Cocaine causes myocarditis or inflammation of the heart muscle. Myocarditis can lead to damage of the heart muscle or cardiomyopathy. As a result, heart failure may occur.

Cardiac arrhythmias. Cocaine can induce a variety of difficult-to-treat cardiac arrhythmias, including the potentially fatal arrhythmias called ventricular tachycardia and ventricular fibrillation.

Stroke. Due to its effect on blood vessels, blood pressure, and blood clotting, stroke is up to seven times more likely in a cocaine user than a non-user.

In general, the treatment of cocaine-induced cardiovascular problems is similar to the treatment of those same cardiac problems when cocaine use is not a factor. However, cocaine use complicates therapy in a few important ways:

• Beta-blockers should not be used in patients taking cocaine. Beta-blockers are very important for the treatment of coronary artery disease, heart attacks, angina, and heart failure. However, in people who have taken cocaine, beta-blockers (which block beta-sympathetic effects of norepinephrine) “uncover” the alpha-sympathetic effects, leading to more constriction of the small arteries, and higher blood pressures. This fact takes a critical treatment tool out of the doctor’s hands when they are dealing with a heart attack.
• When treating what appears to be an acute heart attack, the use of clot-busting drugs — drugs that produce fibrinolysis — should generally not be employed in a cocaine-user without first doing a cardiac catheterization. This is because the ECG changes that typically indicate that an acute heart attack is occurring may be seen in cocaine users who are actually not having a heart attack.
• Doctors are reluctant to use stents to treat coronary artery disease in cocaine users because stent thrombosis (clotting off of the stent) is much higher in these people.

The bottom line is that, not only are the cardiovascular problems caused by cocaine especially dangerous, they are also especially difficult to treat, even by doctors who are very experienced in dealing with these problems.

The use of cocaine can place enormous stress on the heart and the vascular system and can lead to several significant cardiovascular conditions. Furthermore, because of the multitude of negative effects on human physiology, treatment options are limited in people who have cocaine-induced cardiovascular disorders.