Drug Treatment for Heart Failure

Aldosterone is a hormone that causes the kidneys to retain salt and water. Thus, aldosterone antagonists (blockers) directly block the effects of aldosterone (unlike ACE inhibitors which block it indirectly) and help limit fluid retention. These drugs improve survival and reduce hospitalization in people with heart failure.

Angiotensin II is a hormone that triggers release of aldosterone andvasopressin, both of which cause the kidneys to retain salt and water. ACE inhibitors thus help limit fluid retention and are one of the mainstays of systolic heart failure treatment. These drugs not only reduce symptoms and the need for hospitalization but also prolong life. ACE inhibitors reduce blood levels of the hormones angiotensin II and thus aldosterone, which normally help increase blood pressure (see figureRegulating Blood Pressure: The Renin-Angiotensin-Aldosterone System). By doing so, ACE inhibitors cause arteries and veins to widen (dilate) and help the kidneys excrete excess water, thus decreasing the amount of work the heart has to do. These drugs also may have direct beneficial effects on the heart and blood vessel walls.

Angiotensin II receptor blockers (ARBs) have effects similar to those of ACE inhibitors. ARBs are used instead of ACE inhibitors in some people who cannot tolerate ACE inhibitors because of cough, which is a side effect of ACE inhibitors that is less likely with ARBs.

Angiotensin receptor/neprilysin inhibitors (ARNIs) are a newer combination drug for the treatment of heart failure. They include an ARB and a new class of drug, neprilysin inhibitors. Neprilysin is an enzyme involved in the breakdown of certain substances (peptides) that signal the body to excrete sodium. By inhibiting the breakdown of these peptides, these drugs lower blood pressure and increase sodium excretion, lowering the heart's workload. The drugs prolong life better than ACE inhibitors or ARBs alone in people with systolic heart failure.

Beta-blockers are often used with ACE inhibitors to treat heart failure and are another mainstay of heart failure treatment. These drugs block the action of the hormone norepinephrine (which increases stress on the heart) and produce long-term improvement in heart function and survival and are an essential treatment in people with systolic heart failure. Beta-blockers may reduce the force of the heart’s contractions initially, so they are usually introduced after heart failure has first been stabilized with other drugs.

Digoxin, one of the oldest treatments for heart failure, increases the force of each heartbeat and slows a heart rate that is too rapid. Digoxin helps relieve symptoms for some people with systolic heart failure but, unlike other heart failure drugs discussed here, it does not prolong life.

Diuretics ("water pills") are often prescribed when salt restriction alone does not reduce fluid retention. These drugs help the kidneys eliminate salt and water by increasing urine formation and thus decreasing fluid volume throughout the body.

Loop diuretics,such as furosemide, torsemide, or bumetanide, are the diuretics most commonly used for heart failure. These diuretics are usually taken by mouth on a long-term basis, but in an emergency, they are very effective when given intravenously. Loop diuretics are preferred for moderate to severe heart failure.

Thiazide diuretics,such as hydrochlorothiazide, which have milder effects and can lower blood pressure, may be prescribed particularly for people who also have high blood pressure.

Loop and thiazide diuretics can cause potassium to be lost in the urine, resulting in hypokalemia. Consequently, a diuretic that causes potassium levels to increase (a potassium-sparing diuretic) or a potassium supplement may be given as well. For all people with heart failure, spironolactone is the preferred potassium-sparing diuretic and can be used unless kidney function is severely reduced. It can prolong life in people with heart failure.

Taking diuretics can worsen urinary incontinence. However, a dose of a diuretic can usually be timed so that the risk of incontinence does not occur when a bathroom is unavailable or when access to one is inconvenient.

The sinus node is the part of the heart that triggers the beat and sets the heart rate. Ivabradine is the first drug in this class of drugs that slow down the rate of the sinus node. Slowing the heart reduces the workload of the heart and can help reduce how often certain people with heart failure need to be hospitalized.

Sodium-glucose cotransporter-2 inhibitors are used in the treatment of diabetes. In addition to lowering the blood sugar (glucose) level in the blood, they also have beneficial effects on the heart muscle and blood vessels. One drug in this class, dapagliflozin, was shown to decrease heart failure symptoms and improve quality of life in people with systolic heart failure. Another drug in this class, empagliflozin, was shown to reduce hospitalizations for diastolic heart failure.

Vasodilators (drugs that widen blood vessels) make it easier for the heart to pump blood. These drugs, such as hydralazine, isosorbide dinitrate, and nitroglycerin patches or spray, are not used as often as ACE inhibitors or angiotensin II receptor blockers, which are more effective. Nonetheless, people who do not respond to or cannot take ACE inhibitors or angiotensin II receptor blockers can benefit from vasodilators. In a few people with advanced symptoms, these drugs may improve quality and quantity of life when added to ACE inhibitors or angiotensin inhibitors.

Other drugs are sometimes helpful.

If the heart rhythm is abnormal, antiarrhythmic drugs (see table Some Drugs Used to Treat Arrhythmias) may be given.

Doctors have tried using drugs besides digoxin that increase the heart's pumping power, but thus far, none have proved helpful and some increase risk of death.