digoxin

Question 1

what is digoxin used for

Answer 1

Treatment for atrial fibrillation, flutter, heart failure

note: it is a cardiac glycoside that increases the force of myocardial contraction and reduces conductivity within the atrioventricular (AV) node

Question 2

when do you need to reduce the dose of digoxin by half

Answer 2

reduce by half with amiodarone, dronedarone or quinine.

Question 3

name the contraindications for digoxin

Answer 3

• intermittent complete heart block
• myocarditis (inflammation of heart muscle)
• ventricular tachycardia or fibrillation
• Wolff-Parkinson-White syndrome (although can be used in infancy)

Question 4

what are the cautions for use of digoxin (there is a risk of digoxin toxicity)

Answer 4

risk of digitalis toxicity with:

• hypercalcaemia
• hypokalaemia,
• hypomagnesaemia
• hypoxia

Question 5

how is the use of digoxin affected by pregnancy + breastfeeding

Answer 5

• dose may need adjustment in pregnancy

- Amount too small in breastmilk to be harmful

Question 6

what monitoring needs to occur when a patient is on digoxin

Answer 6

renal function and electrolytes (toxicity increased by electrolyte imbalance)

Question 7

what can increase the risk of toxicity for patients taking digoxin

Answer 7

Toxicity increased by electrolyte disturbances

electrolyte disturbances:

• hypercalcaemia
• hypokalaemia
• hypomagnesaemia
• hypoxia

Question 8

what is the ideal therapeutic range for digoxin

Answer 8

1 – 2 micrograms/litre

Question 9

what are the symptoms of digoxin toxicity

Answer 9

Nausea, vomiting, dizziness, fatigue, visual disturbances and bradycardia

Question 10

what are the common side effects of digoxin

Answer 10

Arrhythmias; cardiac conduction disorder; cerebral impairment; diarrhoea; dizziness; eosinophilia; nausea; skin reactions; vision disorders; vomiting

Question 11

how does renal function affect the dose of digoxin

Answer 11

Consider reducing initial and maintenance doses if renal impairment occurs