Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
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, the 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 in 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 either way potassium levels need to be monitored carefully.
Spironolactone and eplerenone are not only mild diuretics but can also be used with stronger diuretics like furosemide (Lasix). They have been shown to prolong life in certain types of heart failure patients when used in combination with angiotensin-converting enzyme (ACE) inhibitors. The patient's physician will know what medication or combinations should be best for each individual; however, it is not uncommon for dosages and medications to be changed by the physician as the disease changes or if better medication becomes available.
Digoxin (Lanoxin): Digoxin is a mild inotrope and, in some cases, is beneficial as an add-on therapy to ACE inhibitors and beta-blockers. Digoxin is an old medicine, used for more than 200 years; it is derived from the foxglove plant. It is the most common form of digitalis.
Digoxin can reduce heart failure symptoms and hospitalizations, but it does not prolong life.
Digoxin is mainly used as an antiarrhythmic to control the rate of the heart in atrial fibrillation and flutter. In contrast, excessive digoxin in the blood can cause life-threatening arrhythmias.
Although commonly used in the past, digoxin has moved far down the list of recommended drugs for treatment of heart failure. It is still considered for patients who are taking ACE inhibitors, ARBs, beta-blockers and/or diuretics and are still experiencing heart failure symptoms.
Vasodilators: These medications enlarge the small arteries or arterioles, which relieve the systolic workload of the left ventricle. Therefore, the heart has to work less to pump blood through the arteries. This also generally lowers blood pressure. Just as importantly, they reduce the levels of certain deleterious hormones and signals that can worsen heart failure.
ACE inhibitors are the most widely used vasodilators for congestive heart failure. 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). Many times the individual drugs are used together as part of a combination pill (for example, Vaseretic, a combination pill containing enalapril and hydrochlorothiazide).
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.
Heart failure is the pathophysiologic state in which the heart, via an abnormality of cardiac function (detectable or not), fails to pump blood at a rate commensurate with the requirements of the metabolizing tissues and/or pumps only from an abnormally elevated diastolic filling pressure.