Drug Therapy
Heart Failure

by Pat Woodbery  MSN, ARNP

Heart Failure

Congestive Heart Failure (CHF)

Heart cannot pump enough blood.

Impaired myocardial contraction

Impaired filling of ventricles

When CHF occurs Compensatory Mechanisms

Increased catecholamines

Increased force of contraction

Increase HR

Increase vasoconstriction

 

Heart Function

AFTERLOAD: Force against which the ventricles eject blood

PRELOAD: Blood return to the heart (Diastolic filling pressure)

 

WORKLOAD: Actual ejection

Digoxin (Lanoxin)

Cardiotonic Effect

Improvement of cardiac pumping

Increased emptying of ventricles

= Increased CARDIAC OUTPUT=

 

 

 

How Does Digoxin Work?

Inhibits cardiac muscle enzyme

Na,K-adenosine triphosphatase

Decreased movement of Na out of the myocardial cells after contraction

Calcium enters the cell in exchange for sodium

This stimulates more Calcium = activated contractile proteins

Increased myocardial contractility

 

 

How Does Digoxin Work?

Slows the rate of ventricular contractions

Depresses cardiac conduction tissues

Depresses AV node

Stimulates Vagus Nerve

Indications for Use of
DIGOXIN

Heart Failure

Atrial Fibrillation

Atrial Flutter

Administration of Digoxin

ORAL

Onset 30 minutes to 2 hours

Peak 6 hours

Intravenous (IV)

Onset 10-30 minutes

Peak 1-5 hours

Digitalization

Administration of an amount of Digoxin sufficient to produce therapeutic effects

Digoxin Toxicity

Nonspecific Early Symptoms

Anorexia, nausea, confusion

Signs and Symptoms of Heart Disease

Atrial Fibrillation

Rapid Ventricular Rate

Rapid Ventricular Response

Diagnosis of
Digoxin Toxicity

Serum Drug Levels

EKG

Treatment of
DIGOXIN TOXICITY

Discontinue Drug

Treat Cardiac Arrhythmias

Digoxin immune fab (Digibind)

Nursing Actions

Check Dosing CAREFULLY

Check Apical Pulse

Give with food or after meals

Inject slowly (over 5 minutes)