Amiodarone

Question 1

Indications of amiodarone

Answer 1

Arrythmias

Question 2

Dosing of Amiodarone

Answer 2

Loading dose:
- 200mg TDS for 7 days then
- 200mg BD for 7 days then
- 200mg maintenance

Has a very long half-life extending to several weeks so only needs to be given once daily

Question 3

Adverse effects of amiodarone

Answer 3

• Corneal microdeposits - drivers may be dazzled by headlights at night (reversible upon withdrawal)
• Phototoxic reactions - so use a wide spectrum sunscreen during treatment and for several months after discontinuing amiodarone
• Persistent slate-grey skin discolouration

Question 4

Toxicity with amiodarone

Answer 4

• Hepotoxicity
• Peripheral neuropathy
• Nausea and vomiting
• Taste disturbance
• Bradycardia

Question 5

Monitoring parameters for amiodarone

Answer 5

1. LFT’s and TFT’s before treatment and every 6 months - amiodarone contains iodine wich can cause both hypothyroidism or hyperthyroidism
2. Chest X-ray - pneumonitis should always be suspected if new or progressive shortness of breath or cough develops
3. ECG
4. BP/ Pulse

Question 6

Amiodarone and warfarin

Answer 6

• Inhibits warfarin metabolism increasing risk of bleeding and enhanced anticoagulant effect

Question 7

Amiodarone and beta blockers

Answer 7

Increased risk of bradycardia, AV block and myocardial depression

Question 8

Amiodarone and lithium

Answer 8

Increased risk of ventricular arrythmias

Question 9

Amiodarone and digoxin

Answer 9

Increases plasma conc. of digoxin by 50%

Question 10

Amiodarone and simvastatin

Answer 10

Increased risk of myopathy (max dose of simvastatin is 20mg)

Question 11

Overview of amiodarone interactions

Answer 11

• Beta blockers
• Warfarin
• Lithium
• Digoxin
• Simvastatin