Cardiac Glycosides

Question 1

Name a cardiac glycoside.

Answer 1

Digoxin

Question 2

What is the main function of digoxin?

Answer 2

Increases the force of myocardial contraction and reduces conductivity within the AV node

Question 3

What is digoxin used for?

Answer 3

Used in HF
Improve exercise tolerance
Reduce hospital admissions
Reduce acute exacerbation episodes

Question 4

How many times is it used and why?

Answer 4

Once due to long half life! But if patient is experiencing S/E TWICE a day

Question 5

What ranges would you see signs of toxicity increase?

Answer 5

1.5 - 3 micrograms/L

Question 6

What is the main toxicity side effect? How would you treat this?

Answer 6

Hypokalaemia.

Take K+ supplements, take potassium sparing diuretics and foods high in K (bananas)

Question 7

What are the main S/E of digoxin?

Answer 7

N/V 
Blurred/yellow vision
weight loss 
Anorexia
Palpitations 
Hallucinations 
Abdominal pain

Question 8

When would someone test their plasma digoxin levels?

Answer 8

Taken 6 hours after ingestion of the dose

Question 9

How is the maintenance dose determined in patients with atrial fibrillation on digoxin?

Answer 9

Ventricular rate at rest and should not fall below 60bpm. Dose is usually calculated by someones renal function.

Question 10

Can all formulations of digoxin have the same bioavailability?

Answer 10

No. Liquids and tablets don’t. If patients need to be switched, they wont be put on the same dose.

Question 11

If a patient does experience digoxin toxicity, what are they treated with?

Answer 11

Digoxin-specific antibody fragment (DigiFab)