What is Clopidogrel?

Clopidogrel, or clopidogrel bisulfate, is an antiplatelet drug that prevents blood clots caused by platelets sticking to each other. This drug is most commonly prescribed to people who experienced a recent heart attack or stroke and need to reduce their risks for another. It also can be used to treat patients with conditions that increase the chances of heart attack or stroke, such as peripheral artery disease (PAD) acute coronary syndrome (ACS).

Antiplatelet drugs work by preventing the formation of blood clots. Blood clots naturally form to stop bleeding from a wound but can be dangerous if they form in response to a blood vessel injury, such as happens when plaque builds up in arteries. Drugs such as clopidogrel prevent such clotting, and as such, are often prescribed to heart attack or stroke patients and to patients who have had heart bypass surgery or who have had a coronary stent placement procedure.

Clopidogrel isn't only prescribed for previous heart attack or stroke survivors, however. It also is sometimes prescribed to patients with PAD or ACS, conditions that increase a patients risk for heart attack or stroke. Statistically, people with PAD are at a higher risk for having a heart attack because they often have blood circulation problems in several places in their bodies, such as their hearts, brains or legs. ACS describes a group of heart conditions that affect how efficiently the heart works and pumps blood, putting these at a higher risk for fatal heart problems as well.

An aspirin regimen may be recommended for people with ACS, due to evidence that aspirin can further decrease the risk for a heart attack. Combining it with clopidogrel can significantly cut a person's heart attack risk when combined with a healthy eating and exercise regimen. Aspirin and clopidogrel should not be taken in combination unless directed by a doctor, however, as both are antiplatelet drugs; the combined effect can be dangerous for some patients.

Serious adverse effects have been reported, some of which require immediate medical treatment. These effects include excessive bleeding, such as uncontrollable nosebleeds; unusual chest pain that does not go away; and having trouble seeing or staying upright. Some people may also find blood in their stools, or they may cough up blood.

As with all antiplatelet drugs, clopidogrel can make it harder for the body to stop bleeding, due to the way it affects platelets in the blood. People who have conditions that cause uncontrolled bleeding usually cannot take this drug. Undergoing surgery while on this drug could be potentially dangerous because the blood may not coagulate well. As such, any patient scheduled for surgery — including dental surgery — should inform his doctor that he is taking clopidogrel; doctors may request a patient stop taking the medication for a week or so before the surgery to reduce the risk of excessive bleeding.