Drugs used for Congestive Heart Failure

Drug List

InotropicDrugs

Drugs affecting the renin-angiotensin-

aldosterone systemDiuretics Beta-blockers Vasodilators

DigoxinDobutamineDopamineMilrinone

CaptoprilEnalaprilatLosartanSpironolactone

FurosemideThiazides

MetoprololCarvedilol

NitratesHydralazineNesiritide

More drugs have been mentioned in the following slides

• Vasodilators: Nitrates that act to directly relax vascular muscle tone and cause decrease in blood pressure with pooling of blood in the veins. The preload and afterload will be decreased

• ACE inhibitors: are agents that block the conversion of angiotensin 1 to angiotensin 2. These drugs causes vasodilatation and decreased blood volume. The afterload will be decreased.

• Diuretics: are employed to decrease the blood volume, which decreased the venous return and blood pressure. The results are decreased preload and decreased afterload.

• Beta agonists: will stimulate the beta receptors in the heart, increasing the myocardial contraction – called positive inotropic effect

• Cardio-tonic drugs: These agents effect the intracellular Ca++ levels in the heart muscle cells leading to increased contractility. The result is increased cardiac output, increased renal blood flow, increased perfusion and increased urine formation. Cardiotonic drugs are:

• Cardiac Glycosides• Phosphodiesterase inhibitors

Cardiac glycosides - Digoxin

• They increase the level of calcium inside the cardiac myocyte by inhibiting the Na+/K+ pump.

• More Ca++ accumulates in the cytoplasm during depolarization and the myocardium will contract forcefully. This is known as positive inotropic effect

• Increased cardiac output• Increased blood flow to the body organs like the kidney

and liver

Effects of Cardiac Glycosides

• Negative chronotropic effect: The heart rate is slowed due to decreased rate of cellular repolarization

• Decreased conduction velocity through AV node

Contraindications and Precautions

• Allergy• Ventricular dysrhythmias• Heart block• Sick sinus syndrome• Acute myocardial infarction• Aortic stenosis• Electrolyte imbalances: Hypokalemia,

Hypomagnesemia, hypercalcemia• Renal failure may cause accumulation of drug

Adverse effects of digoxin

• Headache, weakness, seizures and drowsiness

• Arrhythmias• Signs of digitalis toxicity: anorexia, nausea

and vomiting, visual changes – yellow halo around objects, palpitations or slow heart rate