Congestive Heart Failure (cont.)

Medications

People with heart failure usually take several different medications that work in different ways to lessen heart failure symptoms, to prevent worsening of the underlying disease, and to prolong life.  

Diuretics (water pills): The buildup of fluid is usually treated with a diuretic.

• Diuretics cause the kidneys to remove excess salt and accompanying water from the bloodstream, thereby reducing the amount of blood volume in circulation. With a lower volume of blood, your heart does not have to work so hard. The number of red and white blood cells is not changed.
  
  
• The end result is an improvement of the ability to breathe (clear out water in the lungs) and a lessening of the swelling in the lower body.
  
  
• Most of these drugs tend to remove potassium from the body, but some drugs, such as diuretics containing triamterene or spironolactone, can increase potassium levels, so potassium levels have to be watched carefully.
  
  
• Diuretics commonly used in heart failure include furosemide (Lasix), bumetanide (Bumex), hydrochlorothiazide (HydroDIURIL), spironolactone (Aldactone), eplerenone (Inspra), triamterene (Dyrenium), torsemide (Demadex), or metolazone (Zaroxolyn), or a combination agent (for example, Dyazide).
  
  
• Spironolactone and eplerenone are not only mild diuretics when used with stronger diuretics like furosemide (Lasix), but when used in small doses, (not diuretic doses), they have been shown to prolong life when used in combination with angiotensin-converting enzyme (ACE) inhibitors. This suggests they have additional effects on the myocardium to prevent progression of myocardial scarring and enlargement.
  
  

Inotropes: IV inotropes are stimulants, such as dobutamine and milrinone, that increase the pumping ability of the heart. These are used as a temporary support of a very weak left ventricle that is not responding to standard CHF therapy.

Digoxin (Lanoxin): This drug improves the pumping ability of the heart, causing it to pump more forcefully, a so-called positive inotrope. However, digoxin is a very weak inotrope and is now only an add-on therapy to ACE inhibitors and beta-blockers.

• Although commonly used, not all people receive digoxin because it is less effective than several of the other classes of medications discussed in this article.
  
  
• Digoxin helps relieve symptoms after vasodilators and diuretics have been tried, but it does not prolong life.
  
  
• Digoxin is an old medicine, used for more than 200 years, that is derived from the foxglove plant.
  
  
• This medication can also be used to control the rhythm of the heart (in atrial fibrillation).
  
  
• Excessive digoxin can build up in the blood and cause potentially dangerous abnormal heart rhythms (arrhythmias). The risk of developing arrhythmias is enhanced if the dose is excessive, the kidneys are impaired and do not excrete digoxin from the body properly, or the potassium in the body is too low (low potassium may result from taking diuretics).

Vasodilators: These medications enlarge the small arteries or arterioles, which relieve the systolic workload of the left ventricle. The heart has to work less to pump blood through the arteries. This also generally lowers blood pressure.

• ACE inhibitors are the most widely used vasodilators for CHF. They block the production of angiotensin II, which is abnormally high in congestive heart failure. Angiotensin II causes vasoconstriction with increased workload on the left ventricle, and it is directly toxic to the left ventricle at excessive levels.
  
  
  • ACE inhibitors are important because they not only improve symptoms, but they also have been proven to significantly prolong the lives of people with heart failure. They do this by slowing progression of the heart damage and in some cases improving heart muscle function.
    
    
  • Some common examples of ACE inhibitors are captopril (Capoten), enalapril (Vasotec), lisinopril (Zestril/Prinivil), benazepril (Lotensin), quinapril (Accupril), fosinopril (Monopril), and ramipril (Altace).
     
• Angiotensin II receptor blockers (ARBs) work by preventing the effect of angiotensin II at the tissue level. Examples of ARB medications include candesartan (Atacand), irbesartan (Avapro), olmesartan (Benicar), losartan (Cozaar), valsartan (Diovan), telmisartan (Micardis), and eprosartan (Teveten). These medications are usually prescribed for people who cannot take ACE inhibitors because of side effects. Both are effective, but ACE inhibitors have been used longer with a greater number of clinical trial data and patient information.
  
  
• ACE inhibitors and ARBs may cause the body to retain potassium, but this is generally only a problem in people with significant kidney disease, or in people who are also taking a potassium-sparing diuretic, such as triamterene or spironolactone.
  
  
• Calcium channel blockers are arterial vasodilators that are not used for treatment of heart failure per se because clinical trials have proven no benefit for prolongation of life. Calcium channel blockers are useful for lowering blood pressure if the cause of the CHF is high blood pressure and the patient is not responding to ACE inhibitors or ARBs.
  
  
• Isosorbide dinitrate and hydralazine (BiDil) is a fixed dose combination of isosorbide dinitrate (20 mg/tablet) and hydralazine (37.5 mg/tablet). This drug is indicated for heart failure in black individuals based in part on results of the African American Heart Failure Trial. Two previous trials in the general population of people with severe heart failure found no benefit but suggested a benefit in black patients. Compared with a placebo, this drug showed a 43% reduction in mortality rate, a 39% decrease in hospitalization rate, and a decrease in symptoms from heart failure in black patients.

Nitrates are venous vasodilators that include isosorbide mononitrate (Imdur) and isosorbide dinitrate (Isordil). They are weaker than the ACE inhibitors and ARBs and are primarily used in combination with an arterial vasodilator, such as hydralazine.
 
Hydralazine (Apresoline) is a pure smooth muscle arterial vasodilator that may be used for CHF. Recent trial data have shown hydralazine to be especially effective in African Americans, but it does not replace ACE inhibitors or ARBs. Hydralazine is especially valuable in patients who have poor kidney function and/or are intolerant to ACE inhibitors and ARBs. 

Beta-blockers: These drugs slow down the heart rate, lower blood pressure, and have a direct affect on the heart muscle to lessen the workload of the heart. Specific beta-blockers, such as carvedilol (Coreg) and long-acting metoprolol (Toprol XL), have been shown to decrease symptoms, hospitalization due to CHF, and deaths.

• Beta-receptors are in the heart muscle and in the walls of arteries. The sympathetic nervous system produces a chemical called norepinephrine that is toxic to the heart muscle in prolonged, high doses.
  
  
• Beta-blockers work by blocking the action of norepinephrine on the heart muscle. In the past, doctors treating heart failure thought that blocking norepinephrine was bad and would make the heart worse because norepinephrine is a stimulant that makes the heartbeat stronger. However, clinical trials have proven that beta-blockers gradually improve the systolic function of the left ventricle, thereby improving symptoms and prolonging life.
  
  
• The foundation of modern therapy of systolic heart failure is a combination of ACE inhibitors and beta-blockers. If at all possible, every patient should be on both drugs for improvement of left ventricular function and prolongation of life.

Natriuretic peptides: Nesiritide (Natrecor), or B-type natriuretic peptide (BNP), is a new medication produced by recombinant DNA technology. BNP is normally produced by the heart muscle. When the left and/or right ventricle are under excessive workload, excess BNP is excreted into the bloodstream.

• Because the natural BNP is already increased with heart failure, why additional BNP works is not totally understood. However, giving additional BNP intravenously lowers the pressure in the lungs and is a mild diuretic, so lung water is removed and excreted through the kidneys, resulting in relief of pulmonary congestion.
  
  
• Nesiritide is given into the vein (intravenously [IV]) to help stabilize people whose heart failure is suddenly worse. Commonly used in the emergency department, nesiritide is used to more rapidly stabilize the patient. Some people may not need to be admitted to the hospital.

Getting the most out of your medications involves the following:

• Other medications may be prescribed, depending on the underlying cause of the heart failure or on the medical condition.
  
  
• Keep a diary of daily weight, and bring it to the doctor every follow-up visit.
  
  
• Since people with heart failure are often on many drugs, the likelihood of drug interactions increases. The medications taken for other medical problems may affect what drugs are prescribed for heart failure. Because of this, people are advised to always bring a current list of medications and any other supplements or nonprescription drugs with them every time they visit a doctor. Note that many of these medications come in combination pills under different marketing names.
  
  
• Take your medication as directed by your health care provider. If he or she does not tell you how to take your medication, ask.
  
  
• Follow the recommendations of your health care provider about diet, exercise, and other lifestyle issues.
  
  
• Be sure you are informed about the side effects of your medications.
  
  
• Develop an action plan with your doctor so you and your family know what to do promptly if your symptoms worsen.

Next: Surgery »