What medications are used in the treatment of a heart attack?
If an electrocardiogram (EKG) shows that you are having a heart attack, a number of medications can be used to assist the heart. Medications used to treat heart attacks include those used in the hospital as well as after hospital discharge. Here is a brief description of some of the more common medications used to treat a heart attack.
Blood vessel dilators. Nitroglycerin is a blood vessel dilator, or "vasodilator" - a drug that opens the blood vessel by relaxing the muscular wall of the blood vessel. Nitroglycerin is given by pill or aerosol spray under the tongue, by skin patch, by ointment or intravenously to prevent blood vessel spasm and to minimize the area of damage from the heart attack.
ACE (angiotensin-converting enzyme) inhibitors, another class of vasodilators, are given orally after a heart attack to improve the heart muscle healing process. Examples of ACE inhibitors include captopril (Capoten), enalapril (Vasotec) and lisinopril (Zestril and Prinivil). These medications reduce the stress on the heart, thereby allowing damaged muscles to recover. A related family of drugs called angiotensin receptor blockers (ARBs) have benefits similar to those of ACE inhibitors. Examples include Losartan (Cozaar), Valsartan (Diovan), Irbesartan (Avapro), and Candesartan (Atacand).
Clot busters. Most heart attacks are caused by a blood clot blocking a coronary artery. Using thrombolytic agents or "clot busters" that can break down blood clots and restore blood flow through the artery can limit heart muscle damage. Medications, if given early, also can be effective in reopening arteries. Clot-dissolving medications, also called thrombolytic agents or clot-busters, can open 80 percent of the blocked arteries within 90 minutes. The most commonly used clot-dissolving drugs are tissue plasminogen activators (Activase and Retavase), streptokinase (Streptase and Kabikinase) and anistreplase (Eminase); all are given intravenously. The earlier these drugs are given, the better the chance of opening the artery quickly. If these drugs are given too late (more than 6 hours after the onset of chest pain), most of the damage to the heart muscle has already occurred. Clot-dissolving drugs may be combined with antiplatelet agents, such as aspirin and ReoPro, or anticoagulants, such as heparin and Coumadin. By reducing the tendency of blood platelets to clump and initiate clot formation, antiplatelet drugs lessen the possibility that the artery will reclose and improve chances of survival. An anticoagulant, such as heparin, often given intravenously in the hospital, thins the blood to prevent blood clots and to maintain an open artery during the initial 24 hours after a heart attack. The most serious complication associated with clot-dissolving drugs is excessive bleeding. A small number of patients who receive clot-busting drugs for a heart attack will experience some spontaneous bleeding. Such bleeding is most serious when it occurs in the brain. People who tend to bleed easily or those who have a history of stroke, uncontrolled high blood pressure, recent head or spine injury or recent surgery are not candidates for clot-busting drugs.
Beta blockers. Beta blockers have long been used in the treatment of angina and hypertension (high blood pressure). Beta-blockers help reduce the heart's demand for oxygen by slowing the rate and force of the contraction of the heart. Examples of beta-blockers include propranolol, timolol, metoprolol and atenol. They are most effective in preventing death when given within two weeks of a heart attack. Intravenous beta blockers given within the first several hours of the onset of a heart attack improve the prognosis (outcome) by reducing the size of the infarct (area of dead muscle cells), lowering the chances of a repeat heart attack, and reducing the risk of deadly abnormal heart rhythms such as ventricular fibrillation. Treatment with beta blockers within the first 24 hours of the onset of a heart attack is recommended for all patients who can tolerate them. Beta blocker therapy is especially useful in individuals with continuing or recurrent pain or abnormally fast heart rhythms called tachycardias.
Antiarrhythmic drugs. Heart attack patients are susceptible to developing abnormal heart rhythms. Numerous antiarrhythmic drugs help control or stop these abnormal rhythms. The type of drug used depends on the type of arrhythmia being treated and its underlying cause. Antiarrhythmic agents refers to a variety of drugs used to treat abnormal heart rhythms or arrhythmias associated with a heart attack. These drugs are divided into four classes: Class I antiarrhythmic drugs are sodium channel blockers including drugs such as quinidine, procainamide, and lidocaine. These agents must be used with caution as they can also depress left ventricular function (heart pumping) and promote or cause arrhythmias. Class antiarrhythmic drugs are beta-blockers and examples include atenolol and metoprolol. These agents are used to control supraventricular tachycardias (arrhythmias originating above the ventricles) and also help to suppress dangerous ventricular arrhythmias such as ventricular tachycardia and ventricular fibrillation. Two of class III antiarrhythmic drugs are amiodarone and sotalol. Amiodarone is the most powerful antiarrhythmic drug, but its side effects limit its use. Sotalol is also a beta-blocker, with side effects and other actions similar to those of other beta-blockers. It is used to treat atrial fibrillation and atrial flutter as well as ventricular arrhythmias. Class IV antiarrhythmic drugs are calcium channel blockers, which slow the heart rate and dilate or open up blood vessels. These drugs are used to control abnormally rapid rhythms such as atrial fibrillation as long as signs of heart failure or heart block are not present. Examples include verapamil and diltiazem.
Pain relievers. Major medications used to relieve chest pain include nitrates such as nitroglycerin and narcotic pain relievers such as morphine. Use of nitroglycerin beyond 48 hours is useful if the chest pain returns or if persistent lung congestion due to heart failure occurs. Benzodiazepines, which are minor tranquilizers or antianxiety agents can help relieve anxiety. Morphine is very effective at relieving heart attack pain, which can be excruciating. Beta-blockers injected into a vein can also help control pain by reducing the heart's demand for oxygen. Nonsteroidal anti-inflammatory drugs (NSAIDs) shouldn't be used because they thin the blood and can interfere with clot-dissolving drugs. Morphine and other narcotic pain relievers are used to relieve chest discomfort associated with a heart attack. Repeat dosages of morphine can be given intravenously frequently if breathing remains normal and no signs of toxicity occur. Side effects of narcotic pain relievers include nausea and pruritus (itching).
Lipid-lowering drugs. Heart attack patients usually have their cholesterol levels checked before discharge from the hospital. If their cholesterol levels are high, a lipid-lowering drug may be prescribed. These drugs include the following: Statins inhibit an enzyme used by the liver to manufacture cholesterol. The statins include lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), fluvastatin (Lescol), and atorvastatin (Lipitor). Ezetimibe (Zetia) is a relatively new drug that decreases the absorption of cholesterol through the gastrointestinal tract. It is usually used in combination with a statin by people who do not reach their cholesterol goals with a statin alone. Fibrates are used to lower triglyceride levels and increase high-density lipoprotein levels (the good cholesterol). These fibric acid derivatives include gemfibrozil (Lopid) and fenofibrate (Tricor). Niacin (vitamin B3), given in large amounts, can lower cholesterol levels. These include Niacor, Niaspan and Slo-Niacin. Bile acid binding resins remove bile acids from the intestine, causing the liver to remove cholesterol from the blood to make more bile acids. These drugs include cholestyramine (sold under the brand names Locholest, Locholest Light, Prevalite, Questran and Questran Light) and colestipol (sold under the brand name Colestid).
Antioxidants. Antioxidant vitamins, including vitamin E, vitamin C and beta-carotene (a form of vitamin A), are being studied for their potential health-promoting properties. The data on whether antioxidants reduce the risk of heart disease are inconclusive. The American Heart Association does not recommend they be used to prevent heart disease.
Homocysteine blockers. Recent studies suggest that too much homocysteine (an amino acid in the blood) is related to an increased risk of heart disease. However, this has not been confirmed . Folic acid and B vitamins lower homocysteine levels. The American Heart Association does not recommend the routine use of folic acid or B vitamins to lower homocysteine levels at this time.