Digoxin TDM Flashcards
What is the mechanism of action of digoxin? What is it used for?
It is a cardiac glycoside which increases the force of myocardial contraction to control arrhythmia and AF
Why is TDM used?
To recognise toxicity
To controls drugs with a narrow therapeutic index
To aid in doses for drugs with poor correlation between dose/effect
Which enzyme-inhibiting drugs result in the dose of digoxin being reduced?
Amiodarone
Verapamil
Spirinolactone
CCBs - amlodipine, diltiazem
Macrolides - erythromycin, clarithromycin, azithromycin
What specific parameter should you always check if a patient is on digoxin + diuretic?
Potassium
Digoxin + diuretic can cause hypokalaemia
Which enzyme inducing drug reduces digoxin serum levels?
St Johns Wort
What is the therapeutic range of digoxin?
1-2ng/ml
What range should digoxin levels never exceed due to toxicity?
> 1.5ng/ml
How is digoxin excreted, and hence what should be monitored?
Excreted renally
Must monitor - CrCl, U&E (especially K+), and BP/pulse
Why is a loading dose of digoxin given?
To immediately achieve steady state concentration in the body
