Amiodarone Flashcards
What is the mechanism of action of amiodarone?
- Blocks sodium, calcium, and potassium channels
- Blocks alpha and beta adrenergic receptors
What is the result of amiodarone blocking sodium, calcium, and potassium channels?
It prolongs the cardiac action potential and slows the heart rate
What is the result of amiodarone blocking alpha and beta adrenergic receptors?
It decreases the heart rate and blood pressure
What are the routes of delivery of amiodarone?
IV
PO
What is the problem with administration of amiodarone?
It is highly irritant to the skin
What is done because of amiodarone being highly irritant to the skin?
If a patient requires repeated or continuous infusion of amiodarone, it is recommended to site a central venous catheter
What are the indications for amiodarone?
- CPR
- Rhythm control in AF
- Atrial flutter and tachycardia in WPW
When should amiodarone be given in CPR?
Non-shockable rhythms, or following 3 successful DC shocks
What dose of amiodarone is given for CPR?
300mg IV (diluted in 20ml glucose 5%), then 150mg if required, then IV infusion 900mg/24 hours
What dose of amiodarone is given for arrhythmias?
Initially 5 mg/kg IV, to be given over 20–120 minutes with ECG monitoring, subsequent infusions given if necessary according to response; maximum 1.2 g per day.
What are the contraindications to amiodarone?
- Sinus bradycardia
- Sinoatrial heart block
- Thyroid dysfunction
- Iodine sensitivity
When should amiodarone be used with caution?
- Hypokalaemia
- Severe bradycardia
- Heart failure
- Elderly
What might amiodarone interact with?
- Warfarin
- Digoxin
- Beta blockers
- Calcium channel blockers
- Lithium
- TCAs (SSRIs, amitriptyline etc.)
- Grapefruit juice
What might happen if amiodarone is given with warfarin?
Increased anticoagulant effect
What might happen if amiodarone is given with digoxin?
Increased plasma concentration of digoxin
What might happen if amiodarone is given with beta blockers?
Increased risk of bradycardia and heart block
What might happen if amiodarone is given with calcium channel blockers?
Increased risk of bradycardia and heart block
What might happen if amiodarone is given with lithium?
Increased risk of ventricular arrhythmias
What might happen if amiodarone is given with TCAs?
Increased risk of ventricular arrhythmias
What might happen if amiodarone is given with grapefruit juice?
Increased exposure to amiodarone
What should be remembered when considering the interactions of amiodarone?
It has a long half-life, and drug interactions may occur for several weeks or months after treatment cessation
What monitoring is required with amiodarone?
- Baseline CXR before starting treatment
- Baseline TFTs and LFTs before starting treatment, and re-checked every 6 months
obvs if they’re about to die just go for it yolo
Why is a baseline CXR required before starting treatment with amiodarone?
Due to risk of pulmonary fibrosis
Why is baseline TFTs and LFTs required before starting treatment with amiodarone?
Due to risk of thyroid disease and hepatotoxicity
What are the common side effects of amiodarone?
- Bradycardia
- Thyroid dysfunction
- Pulmonary fibrosis
- Photosensitivity
- Corneal microdeposits
- Peripheral neuropathy
- Jaundice
- Hepatotoxicity
- Vomiting
- Tremor
- Taste disturbances
What are the less common side effects of amiodarone?
- Peripheral neuropathy and myopathy (reversible)
- Conduction disturbances
- Worsening arrhythmias
What are the very rare side effects of amiodarone?
- Alopecia
- Optic neuritis
What counselling needs to be given before treatment with amiodarone? -
- About serious adverse effects
- Photosensitivity
- Optic neuritis
What counselling is required regarding the adverse effects of amiodarone?
Inform the patient of the adverse effects, and emphasise the importance of complying with monitoring
What counselling is required regarding photosensitivity with amiodarone?
Advise patient to protect skin from direct sunlight
What counselling is required regarding optic neuritis with amiodarone?
Counsel patients about signs and symptoms of optic neuritis, and warn them that amiodarone must be stopped immediately as blindness can occur
