Digoxin

Question 1

What is it indicated?

Answer 1

AF
Atrial flutter
HF

Question 2

How does it work?

Answer 2

It reduces the heart rate
It increases the force of contraction

Question 3

What is it contraindicated in?

Answer 3

Arrhythmias caused by previous digoxin use
Heart conduction problems (heart block or atrioventricular heart block)
Ventricular tachycardia

Question 4

When do you use it in caution?

Answer 4

Hypercalcaemia- increased risk of digoxin toxicity
Hypokalaemia- increased risk of digoxin toxicity
Hypomagnesaemia- increased risk of digoxin toxicity
Recent MI
Thyroid disease

Question 5

What electrolyte imbalances can cause digoxin toxicity?

Answer 5

Hypomagnesaemia

Hypercalcaemia

Hypokalaemia- most important as potassium and digoxin compete to bind to the Na+/K+-ATPase pump

Question 6

What are the possible interactions?

Answer 6

Loop diuretics and thiazide diuretics- increase risk of digoxin toxicity by hypokalaemia

Amiodarone, diltiazem, verapamil, spironolactone and quinine- increase concentrations of digoxin causing toxicity

Question 7

What are some of the side effects of this drug?

Answer 7

Bradycardia
GI upset
rash
dizziness
visual disturbance (blurred or yellow vision)

Question 8

What are the monitoring requirements?

Answer 8

Monitor serum electrolytes ad renal function
Monitor for signs of toxicity e.g. confusion, nausea, anorexia or disturbance of colour vision

Question 9

Does the dose need to be adjusted in renal impairment?

Answer 9

Dose should be reduced as digoxin is eliminated by the kidneys