Amiodarone

Question 1

What is amiodarone?

Answer 1

Anti-arrhytmic drug, used particularly when other drugs have been ineffective/contraindicated
Mainly used in AF and atrial flutter, but also
- PSVT
- Nodal and verntricular tachycardia
- VF
- Tachyarrhythmias associated with WPW syndrome

Question 2

Mechanism of action

Answer 2

Blocks K+ channels, prolonging refractory period- also blocks Na+ with high affinity for inactivated channels (weak Ca2+ blocking effect)
Anti-adrenergic effects by non-competitively blocking a+B receptors
- Slows down sinus rate and AV conduction, slightly prolongs QT interval
Can also cause peripheral VD

Question 3

Contraindications

Answer 3

• Severe conduction disturbances (unless pacemaker)
• SN disease (unless pacemaker)
• Iodine sensitivity
• SA heart block (except cardiac arrest)
• Sinus bradycardia (except cardiac arrest)
• Thyroid dysfunction

Question 4

Side effects of amiodarone

Answer 4

Corneal microdeposits, thyroid function (iodine containing), hepatotoxicity, pulmonary toxicity and peripheral neuropathy
Pregnancy- risk of neonatal goitre, only use if no other option
Breastfeeding- avoid: risk of neonatal hypothyroidism

Question 5

Monitoring tests

Answer 5

TFT, LFT, Sreum k+, chest x-ray

Question 6

Interactions

Answer 6

Long half life so many potential interactions
Other anti-arrhytmics, antibacterials (erythromycin, levofloxacin), anticoagulants (coumarins, dabigatran), antidepressants, antiepileptics (phenytoin), antihistamine, antimalarial, antimuscarinic, antiphyscotic, antivirals, beta blockers etc