Other Cardiovascular Medications - Medications For Heart Disease: Heart Disease

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Other cardiovascular medications

Some cardiovascular medications function as antiplatelet drugs, which prevent tiny blood cells known as platelets from clumping together — the first step in the formation of a blood clot. Others dilate blood vessels or provide two medicines in one pill.

Aspirin

Aspirin is an old standby, yet it continues to surprise. This common, inexpensive drug helps protect survivors of heart attack and stroke from subsequent heart attacks and death, and even helps reduce the number of deaths that occur within the first hours following a heart attack. Although aspirin is best known as an antiplatelet drug, it may also subdue the inflammation that is central to coronary artery disease.

Randomized trials have provided clear evidence of aspirin's value in both preventing heart attacks in men and treating coronary artery disease in both sexes. Over all, dozens of studies, involving tens of thousands of people, have shown that low-dose aspirin reduces the risk for heart disease and stroke by about 25%. A standard dose of aspirin to prevent heart attack is 81 mg per day, about what you'd find in a baby aspirin.

Guidelines from nearly every major medical group urge people with heart disease or at high risk for it to take aspirin. Although a major study reported in 2005 concluded that the advice is not as clear-cut for how to prevent first heart attacks in women (see "Advice for women," below), the prevailing consensus remains that in general, unless you are allergic to aspirin or it causes you problems, you should take it if you

• have had a heart attack

• have had an ischemic (clot-caused) stroke or a mini-stroke (transient ischemic attack)

• have angina (chest pain)

• have had a coronary artery bypass or angioplasty

• have diabetes

• are at high risk for heart disease (see Table 6 or 7).

Despite aspirin's benefits, it also has some drawbacks. The evidence that its benefits exceed its risks is much stronger in men than in women, at least in terms of primary prevention (avoiding a first cardiovascular event). It can increase the risk for stroke and significant gastrointestinal bleeding. Even people who take aspirin occasionally with no problems could experience bleeding complications with regular use over prolonged periods. In particular, it may not be a good choice for people with uncontrolled hypertension (a major cause of hemorrhage into the brain). In such people, aspirin could more likely cause dangerous bleeding than prevent a heart attack. In addition, aspirin occasionally irritates the stomach lining without causing bleeding. However, these side effects can be reduced with the use of coated aspirin, which minimizes stomach irritation.

Advice for women. The first large-scale randomized study to specifically examine aspirin's effectiveness in preventing first heart attacks in healthy women, reported in the New England Journal of Medicine in 2005, showed that the risk/benefit analysis for aspirin is not as straightforward in women as it is in men. The study involved almost 40,000 healthy women ages 45 and older, who took 100 mg of aspirin or a placebo every other day. To their surprise, the researchers found that aspirin did not affect the risk for a first heart attack one way or the other in the group as a whole, although it did reduce the risk for stroke by 17%. Yet when the researchers did subgroup analyses, they discovered that aspirin significantly reduced the risk for first heart attack, stroke, and other cardiovascular events in women who were 65 and older. This benefit has to be weighed, however, against an increased risk for gastrointestinal bleeding.

So what do you do? If you're a woman who has already had a heart attack, stroke, or some other cardiovascular event, the advice remains the same: Take aspirin to reduce the risk for a second event. (A large study that looked at such secondary prevention concluded that aspirin benefits both men and women.) But if you're considering taking aspirin to prevent a first event, the advice is less clear-cut. Talk with your physician to determine whether — in your case — the benefits outweigh the risks.

Aspirin resistance. Some people are resistant to aspirin's anticlotting effects. So far the research indicates that aspirin fails to affect platelets' tendency to clump, or does so only partially, in 5%–40% of people who take it. These people therefore don't have the same reduction in heart attack and stroke risk that other people gain from aspirin use.

There are probably several reasons why aspirin resistance occurs. The body's response to aspirin may change over time. Some people have trouble absorbing aspirin from the digestive tract. Smoking blunts the effect of aspirin on platelets, as do being overweight and having high cholesterol or high blood pressure. A variety of genes influence how the body responds to aspirin. Finally, a few studies have indicated that a common nonsteroidal anti-inflammatory drug (NSAID), ibuprofen, may block aspirin's protective effects. The occasional dose of ibuprofen isn't likely to do this, but daily use could.

Although two laboratory tests are available to measure how well aspirin may be working for you, the idea of aspirin resistance is so new that many doctors either aren't aware of it or are waiting for more evidence that it's real before ordering these tests. So what do you do in the meantime? First, talk with your doctor about being tested for aspirin responsiveness. Second, if you need to take an NSAID for arthritis or some other condition, pick one that doesn't interfere with aspirin, such as naproxen (Aleve, Naprosyn) or diclofenac (Cataflam, Voltaren). Third, don't stop taking aspirin — regardless of whether you can get tested or what the results are. Aspirin probably works in several ways to prevent heart attacks. If do you find you are aspirin resistant, talk with your doctor about other antiplatelet medications.

Other antiplatelet medications

Several other options are available to inhibit platelets, but these tend to be more expensive than aspirin and are not as well studied. These include dipyridamole (Persantine, or Aggrenox when combined with aspirin) and clopidogrel (Plavix). One thing to keep in mind, however, is that all the possible side effects of these newer medications are not yet well known. A 2005 study in the New England Journal of Medicine, for instance, reported that people taking Plavix developed 12 times as many ulcers as people who took aspirin and a heartburn pill. Although the study was small, it does make sense to be cautious whenever any new medication hits the market. Certainly this point is underscored by what happened with COX-2 inhibitors (see "Cautions about COX-2 inhibitors," below).

Nitroglycerin

In recent decades, many new heart drugs have been introduced, but they haven't undercut the importance of nitroglycerin and other nitrate compounds. For more than a century, these drugs have been the most important medications for treating coronary artery disease. Nitroglycerin is best known as the little white pills that people carry with them and slip under the tongue when they have bouts of chest pain.

Nitrates help prevent or stop ischemia in several ways. They relax the muscles in the walls of the blood vessels, causing arteries and veins to dilate. When the coronary arteries dilate in response to nitroglycerin, the heart's blood supply increases. Nitrates also reduce the heart's work by lowering the body's blood pressure and the pressure within the heart's chambers. As a result, the heart requires less oxygen and places fewer demands on the coronary arteries.

Because nitrates dilate blood vessels throughout the body, they can cause a wide range of side effects, such as headache, dizziness, and even fainting spells. When people first start taking nitroglycerin, they are usually advised to sit down to avoid falling. Sitting is better than lying down because raising the legs to the level of the heart causes more blood to flow to the heart, increasing its workload.

The problem of tolerance. The effects of regular nitroglycerin tablets come and go quickly, but other forms of nitroglycerin, such as patches and timed-release pills, have longer-lasting effects. Unfortunately, research has shown that around-the-clock exposure to nitrates (as is provided by the patch) produces tolerance, or resistance to their effects. Nitrate tolerance can be minimized if you take nitroglycerin during the day but stop taking it at night, for instance, by removing the patch. These "nitrate holidays" help the body recover its ability to respond to the medication.

Newer nitrate delivery systems, including long-acting isosorbide mononitrates (Ismo, Imdur) accomplish the same thing with a single dose each day. One risk with this approach is that you might be left unprotected during the first hour or so after awakening — a high-risk time for heart attacks. This problem is often addressed by using other long-acting anti-anginal medications in conjunction with the nitrates.

Nitrates and erectile dysfunction medications. If you are taking a nitrate on a regular basis, it is important that you do not use some of the top-selling medications available to treat erectile dysfunction: tadalafil (Cialis), vardenafil (Levitra), or sildenafil (Viagra). These medications can cause a life-threatening drop in blood pressure when used in addition to a nitrate (see "What about sex?"). If you are taking nitroglycerin and are having problems with erectile dysfunction, talk with your doctor about alternatives.

Combination medications

A number of combination medications are available to treat coronary artery disease. Most aim to control high blood pressure by combining a diuretic with a beta blocker, a calcium-channel blocker, ACE inhibitor, ARB, or a different type of diuretic. One combination drug aims to lower unhealthy LDL cholesterol while boosting healthy HDL levels. The combination drug Caduet is intended to lower blood pressure and cholesterol at the same time. Others are in the development pipeline.

Is a combination drug right for you? It depends on your situation. Many people take more than one drug to control blood pressure or cholesterol, for instance. If you find you routinely miss doses or get confused about which medications you have taken, it may make sense to take a combination pill.

Cost is another consideration, especially if you have to make a copayment each time you purchase a medication. Using a combination drug means you would make one copayment instead of two. But if you pay for your medication yourself, or if your health plan charges a higher copayment for brand-name drugs than for generics (as is often the case), a combination could prove more expensive. And keep in mind that some combination drugs include one or more brand-name drugs for which less expensive generic versions are available. Indeed, combination drugs represent a growth industry for drug makers: They can help a company extend high-profit sales of a drug whose patent is about to expire.

Another drawback to combination medications is that it is hard to tinker with the dose, and changing dosage is a fact of life for people using cardiovascular drugs. People often start with low doses of particular medications and then increase them as needed to control one or more factors such as blood pressure, cholesterol, or blood sugar. But in a combination drug, the doses are paired: You can't increase one medication without increasing the other.

So what do you do? Combination drugs probably aren't a good idea if you are just starting drug therapy for a condition, or if your doctor needs to change the dose often. On the other hand, if you have been taking two well-established medications at stable doses for some time, a combination that delivers both of them at the right doses is worth looking into, especially if it contains generic versions of the drugs.

Last updated:	May 03, 2007