Anti-arrhythmics

Question 1

What is an example

Answer 1

Amiodarone

Question 2

What are the common indications for use

Answer 2

• management wide range tachyarrhythmias
• Including AF, atrial flutter, supraventricular tachycardia (SVT), VT or refractory ventricular fibrillation (VF)
• generally only used when other methods ineffective or inappropriate

Question 3

What are the mechanisms of action

Answer 3

• Blocks Na, Ca, K channels
• Antagonism of alpha- and beta-adrenergic receptors
• Reduce spontaneous depolarisation, slow conduction velocity, increase resistance to depolarisation
• Interferes with AV node –> reduce ventricular rate in AF + atrial flutter AND breaks ‘re-entry’ circuit of SVT + returns to sinus rhythm

Question 4

What are the side effects

Answer 4

ACUTE
- Hypotension (during IV infusion) - otherwise causes little myocardial depression
CHRONIC
- Pneumonitis 
- Bradycardia, AV block
- Hepatitis 
- Photosensitivity + grey discolouring 

Thyroid abnormalities - iodine content + similarities to thyroid hormone (–> HYPO + HYPER)

Question 5

What are some contra-indications

Answer 5

• Severe hypotension
• Heart block
• Active thyroid disease

Question 6

What are some interactions

Answer 6

• Interacts with lots of things

- Digoxin/ diltiazem/ verapamil - increases plasma concentrations