DIGOXIN Flashcards
Class
Cardiac glycosides
Digoxin - therapeutic range
Therapeutic Range: 0.7ng/ml -
2.0ng/ml
How can you tell toxic effects are happening?
Toxic risk increases from 1.5 to 3 mcg/litre for digoxin
Indication
- AF/ Atrial flutter
- Only effective at rest
- Role in HF
How do you determine the achieved maintenance dose in
AF with digoxin?
- Determine by the ventricular rate at rest
- Which should NOT fall persistently under 60 BPM
For heart failure, is a loading dose required?
- No, a loading dose is NOT required
- A satisfactory plasma-digoxin concentration can be achieved over a period of about a week
Digoxin’s half-life and dosing
Digoxin has a long half-life and maintenance doses need to be given only once daily
What is the most important determinant of the maintenance dose of Digoxin?
Renal function
CI
- 2nd degree AV heart block
- WPW syndrome
SE - toxicity
- Arrhythmias
- N& V
- Brady
- Blurred/ Yellow vision
- Anorexia
- Confusion, dizziness
SICK + SLOW
What do unwanted effects depend on?
- Both the concentration of digoxin in the plasma and the sensitivity of the conducting system or of the myocardium, which is often increased in heart disease
Which patient group are particularly susceptible to digitalis toxicity and therefore digoxin should be used in caution with them?
elderly
What are the monitoring requirements for Digoxin?
- Plasma-digoxin concentration assay
- Blood should be taken at
least 6 hours after the dose - Serum electrolytes and renal function
- Toxicity is increased by electrolyte disturbances
What electrolytes (when disturbed)
increase the risk of digitalis toxicity?
- Hypercalcaemia
- Hypokalaemia - give K sparing diuretic, potassium suppls
- Hypomagnesaemia
If digitalis toxicity is suspected, what do you do?
- Digoxin should be withdrawn
- Give atropine sulfate
- If life-threatening overdose, give Digoxin-specific antibody fragments
