Amiodarone (High risk) Flashcards
what is amiodarone indicated for?
1) Initiated under hospital supervision for a wide range arrhythmias. It is generally used only when other therapeutic options (drugs or electrical cardioversion) are ineffective or inappropriate.
2) Tachyarrhythmias associated with Wolff-Parkinson-White syndrome
3) cardiac arrest
State the dosage of amiodarone for the treatment of arrhythmias
200 mg 3 times a day for 1 week, then reduced to 200 mg twice daily for a further week, followed by maintenance dose, usually 200 mg
Outline the MoA of amiodarone
Blockade of sodium, calcium and potassium channels, and antagonism of α- and β-adrenergic receptors. These effects reduce spontaneous depolarisation , slow conduction velocity and increase resistance to depolarisation, including in the atrioventricular (AV) node.
what was the MHRA/CHM advice regarding concomittent use of amioderone with Sofosbuvir daclatasvir and ledipasvir?
Risks of severe bradycardia and heart block when taken with amiodarone
who should amiodarone generally be avoided in? (3)
Those with:
1) severe hypotension
2) heart block
3) active thyroid disease
who should amiodarone be used in caution with? (4)
1) Elderly
2) heart failure
3) hypokalaemia
4) severe bradycardia
What side effect can amiodarone cause, when given parenterally?
hypotension (following rapid injection)
When taken chronically, amiodarone has many side effects, several of which are serious. List some of these common side effects (5)
1) Lungs: pneumonitis
2) Heart: Bradycardia, AV block, Arrhythmias
3) Liver: hepatitis
4) skin photosensitivity and grey discolouration-
5) may cause thyroid abnormalities, including hypo- and hyperthyroidism
List the 4 drug specific side effects of amiodarone and outline how they should be managed (4)
1) Corneal microdeposits - Reversible on withdrawal of treatment. However, if vision is impaired or if optic neuritis or optic neuropathy occur, discontinue to prevent blindness and seek advice
2) Thyroid function - contains iodine and can cause; both hypothyroidism and hyperthyroidism. Hypo can be treated with replacement therapy without withdrawing amiodarone if essential
3) Hepatotoxicity -discontinue if severe liver function abnormalities or clinical signs of liver disease develop.
4) Pulmonary toxicity- Pneumonitis should always be suspected if new or progressive SOB or if cough develops in a patient taking amiodarone.
When compared with other antiarrhythmic drugs, does amiodarone cause myocardial depression when used acutely?
In acute use, compared with other antiarrhythmic drugs, amiodarone causes relatively little myocardial depression.
Amiodarone has an extremely long half-life, after discontinuation it might take many months to clear. Why can this be a problem?
There is potential for drug interactions to occur for several weeks (or even months) after treatment with it has been stopped.
List the main drugs that amiodarone can interact with and explain how these interactions should be managed
1) Increases plasma concentrations of : DIGOXIN DILTIAZEM and VERAPAMIL
2) This may increase the risk of bradycardia, AV block and heart failure. The doses of these drugs should be halved if amiodarone is started
Can amiodarone be used in pregnancy and breastfeeding?
1) Pregnancy: Possible risk of neonatal goitre: use only if no alternative
2) Breastfeeding: Avoid- present in milk in significant amounts
Outline the monitoring requirements for amiodarone (5)
1) Thyroid function tests should be performed before treatment and then every 6 months
2) LFT’s required before treatment and every 6 months.
3) Serum potassium measured before treatment
4) Chest x-ray required before treatment
5) monitor renal function
what should be monitored if amiodarone is given via the IV route? (2)
1) ECG monitoring
2) Monitor liver transaminases
