Drug Therapy

Beginning in the late 1950s, doctors began to make great strides in the fight against heart disease. In 1959, Swedish doctors implanted the first pacemaker in a 43-year-old man. In 1961, researchers at Johns Hopkins University found that a combination of simple and easily learned resuscitative techniques such as CPR could keep heart-attack victims alive long enough to get them to a hospital and more sophisticated care.

We have learned more about the causes of heart disease and the roles life-style and diet play. In addition, we have now refined surgical techniques like valve replacements and transplants to treat damaged hearts.

Researchers developing medications for heart disease have had a wide range of problems to deal with. We've needed drugs first to forestall heart and vascular disease, then to correct the resulting conditions. Many new drugs have been developed and tested. The first real breakthrough came with the discovery of a surprisingly versatile group of drugs called beta-blockers, but we still find extremely useful some drugs discovered more than two centuries ago.

There are a wide variety of drugs that are commonly used to treat patients with heart diseases.

Digitalis

Digitalis (Digitoxin and Digoxin) is a drug class that was first discovered 200 years ago by Dr. William Withering in an ingredient in foxglove, a common flower in English gardens. It was used to treat a condition called dropsy, which we know today as congestive heart failure. It occurs when an overworked heart can't pump enough blood to meet the body's circulatory needs.

Digitalis affects the heart muscle by invigorating it and causing it to pump with more force. By beating more powerfully and pumping more blood with each beat, the heart doesn't have to beat as quickly. This also explains the drug's other effects. By strengthening the heartbeat, it almost magically reverses the symptoms of congestive heart failure. Blood passes through the kidneys more quickly, enabling them to eliminate the excess fluid and salt; a heart that has enlarged may shrink back toward its normal size. The overall result is an improvement of circulation throughout the body. Digitalis continues to be an extremely useful drug. Nonetheless, there are limits to what it can do. Today this drug and others may be combined in a comprehensive cardiac care program.

Nitroglycerin

Nitroglycerin and related drugs trace their ancestry to the chemist's test tube. Amyl nitrite, first synthesized in 1844, was quickly found to cause flushing of the face due to the relaxation of the tiny blood vessels known as capillaries. Twenty-three years later, a young Scottish medical student by the name of Thomas Lauder Brunton suspected that amyl nitrite might also relieve angina by increasing blood flow to the heart. It wasn't long before nitroglycerin, which is chemically similar to amyl nitrite, was discovered to have a similar effect, relaxing the smooth muscles that are part of your arteries, allowing them to dilate. Both drugs are still used for treatment of angina, but nitroglycerin is by far the more common, because it is more easily administered and has fewer side effects.

One new way of delivering nitroglycerin (as well as some other drugs) is by means of a transdermal patch. For years doctors have known that nitroglycerin is easily absorbed into the bloodstream through the skin. There are nitroglycerin ointments that can be spread on the skin, tablets that are held under the tongue or in the cheek until they dissolve, and capsules that can be swallowed. The advantage of transdermal patches, which look like big adhesive bandages, is that they regulate the delivery of the drug, providing a constant amount of it for as long as 24 hours at a time.

Beta-Blockers

Various nerve systems in the body stimulate the activity of the heart. The beta-adrenergic system was discovered to be involved in irregular heartbeats. Scientists began looking for a drug that would block the activity of this system and ended up with a drug that became one of the most valuable medications we have.

In 1967, the first beta-blocker was approved for the treatment of irregular heartbeats (arrhythmias). Since then the FDA has expanded the approved uses of the drug to include treatment of angina, high blood pressure, and migraine headaches. Doctors have also researched its value for unapproved uses including anxiety and serious thyroid disease. These multiple uses qualify beta-blockers among the most versatile drugs ever discovered, but their most important use was yet to come.

Despite advances in technology and treatment, doctors knew that people who have one heart attack are at increased risk for a second.

In 1981, cardiologists conducting a study of beta-blockers found that it not only helped prevent second heart attacks, but it also reduced mortality rates among heart patients by 26 percent. The study ended nine months early, because it would be unethical to withhold the drug from the control group of patients. The study's sponsor, the National Heart, Blood, and Lung Institute, estimated that appropriate use of the drug could save hundreds of thousands of lives a year in the United States alone. Thus, drugs in the beta-blocker class have become extremely useful in reducing the pain and suffering of heart disease.

Commonly Used Beta-Blockers:

Atenolol (Tenormin)
Metoprolol (Lopressor)
Propranolol (Inderal)
Toprol XL (Sustained release Metoprolol)

The Calcium Channel Blockers

When verapamil (Isoptin, Calan), the first calcium channel blocker, was approved by the FDA in 1982, its sole use was for the treatment of arrhythmias (irregular heartbeats), and often it wasn't even the drug of first choice for that condition. If your doctor wanted to give you verapamil, you'd have to be in the hospital to get it, since it was only available in an injectable form. In fact, verapamil was thought to be so unpromising that nobody thought much about how it worked or what beneficial effects it might have other than controlling irregular heartbeats.

This situation changed when cardiologists began to study propranolol and the other beta-blockers. Their success with these drugs prompted increased research into other drugs that act upon the heart. When researchers began looking around, they found that verapamil had a lot more potential benefits to offer heart disease victims than anyone had ever guessed.

Your heartbeat is controlled by tiny electrical impulses; that's why doctors sometimes use electronic pacemakers to regulate hearts that don't beat the way they should. Calcium plays a key role in regulating the heart's response to these electrical signals. It flows between the heart cells and surrounding fluid through a sort of chemical revolving door – the calcium channel. The more calcium that gets through the door before the electrical signal comes, the more strongly the heart contracts and the harder it works. Calcium channel blockers, like verapamil and its cousins, don't quite "lock" the revolving door, but they significantly slow it down. This eases the load on a damaged heart and, for many patients, improves heart functioning.

If you suffer from angina, you'll be interested to know that calcium channel blockers have turned out to be among the most effective antianginal medications ever discovered. They help your heart work with less effort; and at the same time, they relax the coronary arteries, improving the supply of oxygen-enriched blood to the heart itself. The result is almost as if the drug told your heart to sit back, relax, and take a few deep breaths.

Commonly Used Calcium Channel Blockers:

Diltiazem (Cardizem)
Felodapine (Plendil)
Nifedipine (Procardia)
Nicardipine (Cardene)
Verapamil (Calan)

Calcium Blockers and the Future

What about the future of this new class of drugs? Researchers are still exploring their potential, and some promising possibilities include the prevention of heart attacks and slowing of atherosclerosis. Other possible uses include treatment of migraine headaches, Raynaud's phenomenon (a condition in which arteries in the extremities spasm, causing pallor), menstrual cramps, and premature labor. Researchers also speculate that calcium channel blockers may someday help in the treatment of strokes, spinal-cord injuries, certain types of kidney failure, and even cancer.

Cholesterol-Reducing Drugs

One in four Americans is at higher risk for heart disease because of elevated cholesterol levels, which are either inherited or acquired due to diet or another disease. Over the past 20 years, physicians and researchers have recognized that high cholesterol levels in both men and women are an important risk factor in cardiovascular diseases. (See your physician to evaluate your own risk levels.) While cholesterol levels can be controlled somewhat by diet alone, adding a medication is the most effective way of lowering them.

Cholesterol-lowering drugs act by preventing the body from manufacturing cholesterol, reducing absorption of dietary cholesterol, or combining with cholesterol to remove it from the bloodstream.

Commonly Used Cholesterol-Lowering Drugs:

Lescol
Lopid
Mevacor
Pravachol
Questran
Zocor
Niacin
Lipitor

Drugs Used for Unblocking Clogged Arteries (Thrombolytics)

Heart attacks usually occur because the coronary arteries become clogged by a blood clot, and some of the most promising new drugs work to unclog them directly. These drugs offer an alternative to coronary artery bypass surgery, in which surgeons take lengths of veins from a patient's leg or chest wall and attach them to the coronary arteries to provide a "detour" around blockages.

These medications work by dissolving blood clots. Blood passing through arteries filled with arterial plaque tends to clot, cutting off the blood supply to tissues downstream.

Depending upon where they create a blockage, blood clots can cause strokes, heart attacks, or life-threatening pulmonary emboli (blockages in the lung). If these clot-dissolving drugs can be given quickly enough, they can reverse these conditions before heart muscle or lung tissue dies from lack of oxygen.

Studies of these drugs show that the sooner they are administered, the more effective they will be. In the future, Emergency Medical Teams may use these drugs when heart attack victims are being transported to the hospital, thus preventing even more deaths.

In the normal, healthy person, these effects aren't dangerous, but if the heart is diseased or damaged, they can be disastrous. If the coronary arteries of a diseased heart tighten up, you'll feel pain (angina) that tells you that your heart is starved for oxygen. If they tighten more, or if the heart has to work harder, the oxygen shortage becomes even more severe. The heart falters – parts of it may even die from lack of oxygen – and you experience a heart attack.

Commonly Used Thrombolytics:

Aggrestat
Integrilin
TPA

Anti-Platelet Drugs

There are numerous drugs that are commonly used in patients with heart attacks that, act on blood cells called platelets. The platelets are responsible for forming blood clots inside the arteries. These drugs inhibit the activation of platelets and thereby prevent blood clots. Patients who are on these medications should be careful about not hurting themselves in any way as they may have bleeding problems. Moreover patients who have history of stomach ulcers should be very careful when they take these medicines. Some of these medicines are also used when patients undergo angioplasty and stenting procedures in the hospital.

Commonly Used Anti-Platelets:

Reopro
Plavix
Aggrestat
Integrilin

ACE Inhibitors

This is a category of medications used in the treatment of heart failure, high blood pressure, and coronary artery disease. "ACE" (angiotensin converting enzyme) is a natural substance that regulates salt and fluid balance. ACE Inhibitors have shown to be very effective in improving survival in patients with chronic heart failure and coronary artery disease. They also provide benefit in the treatment of high blood pressure, especially in diabetic patients. Side effects from ACE Inhibitors are uncommon, but may include persistent cough, elevated potassium levels and, very rarely, allergic reactions.

Commonly Used ACE Inhibitors

Quinapril (Accupril)
Ramipril (Altace)
Captopril (Captopril)
Benzapril (Lotensin)
Benzapril plus amlodipine (Lotrel)
Fosinopril (Monopril)
Lisinopril (Prinivil or Zestril)
Lisinopril plus hydrochlorothiazide (Prinzide or Zestoretic)
Enalapril (Vasotec)

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