CARDIAC-GLYCOSIDES
CARDIAC-GLYCOSIDES means
- CARDIAC: relating to the heart.
- GLYCOSIDES: are organic molecules that can be isolated from plant or animal sources.
The most commonly used cardiac glycoside is digoxin.
MAIN SOURCE OF DIGOXIN
COMMON NAME WOOLLY FOXGLOVE
SCIENTIFIC NAME: DIGITALIS LANATA
DOSAGE FORMS of digoxin
It is available as brand Lanoxin and generic digoxin in the following dosage.
62.5 mcg (.0625 mg) oral tablets
125 mcg (0.125 mg) oral tablets
250 mcg (0.25 mg) oral tablets
50 mcg (0.05 mg)/mL oral solutiona
Digoxin is also available in injectable forms
USE OF DIGOXIN
The drug is most useful in the treatment of Supraventricular tachycardias (svts) Control the ventricular rate in atrial fibrillation (AF) or atrial flutter.
Treatment of heart failure
MECHANISM OF ACTION
The slowing of cardiac rate and rhythm are attributed to digoxin’s impact on the central nervous system (CNS) which leads to increased vagal activity resulting in slowed conduction in the atrioventricular (AV) node.
In AF, it slows the ventricular rate largely by
↓ The sympathetic drive
↓ Conduction across the atrioventricular (AV)node.
↑ The force of contraction and provides inotropic support.
Inhibition of the Na*/K*/ATPase pump on the cell membranes of cardiac myocytes results in ↑intracellular sodium.
This ↑ in intracellular sodium inhibits the sodium- calcium exchanger, and thus ↓ the efflux of calcium ions, resulting in an ↑ in intracellular calcium.
↑ intracellular calcium results
in ↑ contractility.
NURSING CONSIDERATIONS
Ensure blood digoxin levels are monitored to prevent toxicity.
Monitoring of blood potassium levels is very important because
hypokalaemia can increase the likelihood of digoxin toxicity.
Digoxin might need to be stopped before cardiac surgery to ‘ the risk
of arrhythmias or bradycardia postoperatively.
Teach patients taking digoxin at home how to accurately take
their Own pulse.
