Name
- Digoxin.
Class of drug
- Cardiac glycoside.
Uses
Action
- Inhibits Na-K ATPase → increased intracellular Ca → increased force of myocardial contraction.
- Acts on SA & AV node → increased refractory period and decreased conduction velocity → slower heart rate.
- Slower heart rate + increased force of contraction = increased cardiac output.
- Normalizes baroreceptor reflexes impaired in heart failure.
- Increases vagal tone.
Indications
- Myocardial failure.
- Supraventricular tachycardia.
- Congestive heart failure
.
Adverse reactions
Effects of overdosage
- Discontinue immediately if signs of toxicity occur and measure serum [digoxin].
Other reported reactions
- Anorexia.
- Vomiting.
- Diarrhea.
- Depression.
- Seizures.
Arrhythmias
- Complete or incomplete heart block .
- Bigeminy.
- Paroxysmal ventricular or atrial tachycardia with block .
- Multifocal ventricular premature contractions (VPCs).
- ALL arrhythmias have been reported with digoxin toxicity .
Investigation of adverse reaction
- Serum [digoxin]: if response inadequate or toxicity observed.
- Therapeutic serum levels are 1-2 ng/ml.
Treatment
- Lidocaine may be used to control digitalis-associated may be used to control digitalis-associated arrhythmias.
Antidote for overdose
- 'Digibind' - digoxin-binding antibody fragments can be administered in life-threatening situations. Very expensive.
