These drugs are given to prevent blood clots from forming. Blood clots may cause a stroke in people with certain types of arrhythmias (such as atrial fibrillation). Anti-clotting agents (either anticoagulants - blood thinners-or drugs that interfere with the function of platelets), also are used to treat unstable angina (heart-related chest pain) and protect against heart attacks. These medications must be carefully regulated so that the body maintains its ability to form clots to stop bleeding in the event of injury.
Anticoagulants
Anticoagulants used to prevent stroke in patients with atrial fibrillation or atrial flutter include:
Warfarin (Coumadin®) usually is prescribed for patients who are over age 65, have had a prior stroke or have other health problems such as heart failure, coronary artery disease, diabetes, hypertension, or heart valve disease. A "blood thinner," it also is used for treatment and prevention of deep vein thrombosis (blood clots in the legs) and to treat pulmonary (lung) embolus (blood clots) and to prevent clots from forming after a heart attack (myocardial infarction).
Anti-platelet Medications
Platelets are blood cells that contribute to clot. Anti-platelet medications also may be given to patients who have survived a heart attack or stroke or have a tendency to form clots. Anti-platelet medications are less effective at preventing clot or stroke than warfarin for patients with atrial fibrillation.
They include:
- Aspirin (or no medication) may be used for people under age 65 who do not have any other risk factors that increase their chances for developing blood clots associated with an atrial fibrillation or atrial flutter. Aspirin also is used to reduce the risk of death or heart attack in patients with coronary artery disease. It is a drug used for unstable angina and has been shown to reduce the risk of recurrent transient ischemic attacks ("mini" strokes) and stroke.
- Ticlopidine (Ticlid®) is used to prevent blood clots following coronary stent placement.
- Clopidogrel (Plavix®) also reduces the risk of stroke in patients who have experienced a transient ischemic attack (temporary blockage of the blood supply to the brain). It is also used by patients who are intolerant to aspirin.
- Dipyridamole (Persantine®). Dipyridamole is also sometimes used as part of a medical test that shows how well blood is flowing to your heart.
- Glycoprotein IIb/IIIa receptor antagonists thin blood by blocking platelets. These agents are very powerful and are given intravenously. They are usually prescribed to prevent blood clots after patients who undergo angioplasty or other procedures to open clogged blood vessels, or to people with the unstable ischemic syndromes (also called unstable angina or acute coronary syndrome). This syndrome is usually, but not always, caused by coronary artery disease (CAD) in which the coronary arteries are blocked or narrowed, reducing the flow of blood and oxygen to the heart (ischemia). People with ischemic disease are at increased risk of heart attack (myocardial infarction), stroke and peripheral vascular disease (PVD). Ischemic heart disease contributes to more deaths (24 percent in the U.S.) than any other cause. Unstable angina is characterized by frequent and severe attacks of chest pain due to an inadequate supply of blood to the heart.
These medications appear to effectively reduce the risk for heart attack or death in many patients, and include:
- abciximab (ReoPro®)
- eptifibatide (Itegrelin®)
- tirofiban (Aggrastat®)
