Digoxin + Amiodarone Flashcards
Question
Answer
What is the drug action of Digoxin?
Digoxin is a cardiac glycoside that increases the force of myocardial contraction and reduces conductivity within the atrioventricular (AV) node.
What are the indications and doses for Digoxin?
Maintenance for atrial fibrillation or flutter:
Maintenance 125–250 micrograms daily,
Heart failure (for patients in sinus rhythm): 62.5–125 micrograms once daily,
reduce dose in the elderly.
What are some contraindications for Digoxin?
Contraindications include
* constrictive pericarditis (unless to control atrial fibrillation or improve systolic dysfunction—but use with caution),
* hypertrophic cardiomyopathy (unless concomitant atrial fibrillation and heart failure—but use with caution),
* intermittent complete heart block, myocarditis,
* second degree AV block,
* supraventricular arrhythmias associated with accessory conducting pathways e.g. Wolff-Parkinson-White syndrome
(although can be used in infancy), and ventricular tachycardia or fibrillation.
What are some cautions to consider when using Digoxin?
Cautions include
- hypercalcemia,
- hypokalemia,
- hypomagnesemia
- hypoxia
( increasing the risk of digitalis toxicity for above ), - recent myocardial infarction,
- severe respiratory disease,
- sick sinus syndrome,
- thyroid disease.
What are common or very common side-effects of Digoxin?
- arrhythmias,
- cardiac conduction disorder,
- cerebral impairment,
- diarrhea, dizziness,
- eosinophilia,
- nausea, and vomiting.
- skin reactions,
- vision disorders,
In case of an overdose of Digoxin, what action should be taken?
Digoxin should be withdrawn,
Serious manifestations require urgent specialist management.
How should Digoxin be administered intravenously?
For intravenous use, avoid rapid intravenous administration (risk of hypertension and reduced coronary flow).
For intravenous infusion (Lanoxin®),
give intermittently in Glucose 5% or Sodium chloride 0.9%;
dilute to a concentration of not more than 62.5 micrograms/mL.
To be given over at least 2 hours.
What is the advice for patient and carer when using Digoxin elixir?
Patient counseling is advised for Digoxin elixir (use pipette).
How should Digoxin be monitored in terms of therapeutic drug monitoring?
For plasma-digoxin concentration assay,
blood should be taken at least 6 hours after a dose.
Monitoring of patient parameters should include
* ** serum electrolytes
* **Renal function,
Toxicity can be increased by electrolyte disturbances.
What forms of Digoxin are available from special-order manufacturers?
special-order manufacturers include
oral suspension,
oral solution,
Solution for injection.
How do formulations of Digoxin differ
Vary in Bioavailability
Whatis the loading dose of digoxin for AF
125-250 mcg OD
What is the therapeutic range for Digoxin
**0.7 - 2 ng/ml**
What is the toxicity risk range for Digoxin
1.5 - 3 ng/ml
