Medications Used to Treat Heart Attack
Treatment may include the following:
Several new "clot-busting drugs," called thrombolytic agents, can help dissolve blood clots and prevent further heart damage. Although clot-busting drugs (e.g., r-PA, t-PA, tnk-PA, streptokinase) are most effective when administered within the first several hours of a heart attack, they are beneficial when administered within 12 hours following the onset of symptoms.
These medications are not used in all cases, and whether they are used or not is determined primarily by electrocardiogram results. Thrombolytic agents carry a small risk for causing excessive bleeding, which can cause stroke if it occurs in the brain; however, potential benefits usually outweigh the risk.
Heparin is a drug used to "thin" the blood to help prevent further blood clot formation. This drug may be particularly useful in patients who experience intermittent blood clot formation within a coronary artery.
The older form of heparin, called unfractionated heparin, usually is administered via a continuous intravenous (IV) infusion. Frequent blood tests are required during treatment to monitor how "thin" the blood is.
Newer forms of heparin, called low molecular weight heparins, usually are administered via injection in the abdomen twice a day. These medications include enoxaparin (Lovenox®), dalteparin (Fragmin®), and nadroparin (Fraxiparin®). Low molecular weight heparins require less frequent monitoring and several studies suggest that this form of the drug prevents recurrent heart attack and death more effectively than unfractionated heparin.
Taking an aspirin during a heart attack and each day following a heart attack can decrease the risk of dying from the condition by almost 25%. Blood clots primarily are composed of platelets (microscopic particles that circulate in the bloodstream) that "stick" to ruptured plaques and to each other. Aspirin makes platelets less "sticky," decreasing the risk for further blood clot formation.
Studies have shown that some patients are resistant to the effects of aspirin therapy. Regular blood tests may be performed to monitor the patient's response; the results of these tests can be used to adjust the aspirin dosage or change the medication.
These drugs slow the heart rate and decrease the strength of the heart's contractions, reducing strain on the heart and its oxygen requirement. Commonly used beta-blockers include metoprolol (Lopressor®, Toprol XL®) and atenolol (Atenolol®). These drugs usually are administered intravenously (through a vein) at first and then orally.
Studies have shown that taking beta-blockers during and after a heart attack decreases the risk for recurrent heart attack and death. Therefore, patients without contraindications to beta-blocker therapy often take these drugs indefinitely. Beta-blockers may cause erectile dysfunction.
Nitroglycerin is a chemical that opens up (dilates) arteries and veins and increases blood flow to the heart. During heart attack, nitroglycerin can be placed under the tongue, where it quickly dissolves and is absorbed into the bloodstream.
Nitroglycerin also can be administered via continuous intravenous (IV) infusion; applied to the skin in cream or patch form, where it is slowly absorbed; or administered as short- or long-acting nitrate pills. Isosorbide dinitrate (Isordil®) usually is taken 3 times a day and isosorbide mononitrate (Ismo®, Imdur®) is taken either twice (Ismo) or once daily (Imdur).
Because nitroglycerin dilates not only the coronary arteries, but also other blood vessels, it may cause severe headaches. In some cases, headaches are so severe that patients are unable to tolerate nitroglycerin therapy.
These drugs help to prevent platelets from sticking together and forming blood clots. They also help dissolve existing blood clots. Studies show that treatment with IIb/IIIa inhibitors can reduce the risk for recurrent heart attack or death. IIb/IIIa inhibitors include eptifibatide (Integrelin®), tirofiban (Aggrastat®), and abciximab (ReoPro®).