CARDIAC GLYCOSIDES AND INOTROPIC AGENTS

·         Inhibit sodium-potassium pump thus increasing intracellular calcium for more efficient contraction of cardiac muscle fibers

·         Action: positive inotropic (increased myocardial contraction , ↑ stroke volume), negative chronotropic (decreased heart rate), negative dromotropic action (decreased conduction of heart cells)

·         Indication:

o    CHF, atrial fibrillation, atrial flutter, atrial tachycardia

·         Contraindication:

o    Ventricular dysrhythmias, 2^nd or 3^rd degree heart block

·         Use with caution:

o     Acute MI, renal disease, hypothyroidism, hypokalemia

Example:

digoxin (Lanoxin®)

digitoxin (Crystodigin®)

milrinone (Primacor®)

amrinone (Inocor®)

nesiritide (Natrecor®)

Side Effects:

·         Bradycardia	·         Arrythmias
·         Headache	·         Nausea and vomiting
·         Hypotension	·         Abdominal pain
·         Visual disturbances

Digitalis Toxicity:

·         Anorexia

·         Diarrhea

·         Nausea and vomiting

·         Bradycardia

·         PVC

·         Cardiac dysrhythmias

·         Headaches

·         Malaise

·         Blurred vision

·         Visual illusions (white, green, yellow halos around objects)

·         Confusion and delirium

Nursing Considerations:

ü  Assess for signs and symptoms of toxicity.

ü  Check apical pulse rate before administering digoxin. Do not administer if HR is <60 bpm.

ü  Check for signs of peripheral and pulmonary edema.

ü  Check serum digoxin level.

o    Normal therapeutic range: 0.5 to 2.0 ng/ml

o    Maintenance dose: 0.125 to 0.5 mg/dl

o    Indicative of digitalis toxicity: >2.0 ng/ml

o    Antidote for digitalis toxicity: Digoxin immune Fab (Ovine^®, Digibind^®)

ü  Report if hypokalemia is present. Digitalis should be discontinued until serum potassium level is sufficient. 

ü  Provide patient teachings:

o    Teach patien about importance of compliance with drug therapy.

o    Check PR before administering drug.

o    Instruct to report side effects.

o    Advise patient to eat foods rich in potassium (fresh and dried fruits, fruit juices, vegetables, potatoes).