Drugs CCC Flashcards
What class of drug is amiodarone?
Class III anti-arrhythmic medications
Indications of amiodarone?
1) Rhythm control in a wide range of tachyarrhythmias e.g. atrial fibrillation, atrial flutter, supraventricular tachycardia (SVT), ventricular tachycardia (VT), refractory ventricular fibrillation (VF)
2) Used in cardiac arrest (given for VF or pulseless VT)
Mechanism of amiodarone?
1) Blockade of sodium, calcium and potassium channels
2) Antagonism of a- and b- adrenergic cells
These effects reduce spontaneous depolarisation, slow conduction velocity and increase resistance to depolarisation (refractoriness), including in the AV node.
How does amiodarone work in AF?
1) Amiodarone interferes with AV node conduction so reduces ventricular rate
2) This increases chance of conversion to sinus rhythm
3) Suppresses spontaneous depolarisations so cardiac muscle cell excitability is reduced –> preventing and treating abnormal heart rhythms
Half life of amiodarone?
What does this mean?
58 days –> loading dose is often required
Side effects of amiodarone?
Acute use –> amiodarone causes relatively little myocardial depression compared to other antiarrhythmics
Chronic use:
- Pneumonitis
- Hepatitis
- Skin: photosensitivity and grey discolouration
- Thyroid abnormalities: due to iodine content and structural similarities to thyroid hormone
Contraindications of amiodarone?
1) Severe hypotension
2) Heart block (except in cardiac arrest)
3) Active thyroid disease (thyrotoxicosis, hyperthyroidism, hypothyroidism)
4) Iodine sensitivity
How can amiodarone affect the thyroid?
Amiodarone can lead to both hypothyroidism (amiodarone-induced hypothyroidism) and less commonly hyperthyroidism (amiodarone-induced thyrotoxicosis).
What blood tests are needed for amiodarone monitoring?
- TFTs
- U&Es
- LFTs
Amiodarone can increase the conc of what 3 drugs?
1) Digoxin
2) Diltiazem
3) Verapamil
This may increase risk of bradycardia, AV block and HF
Indications for flecainide?
1) Rhythm control (pharmacological cardioversion) in supraventricular tachycardia (e.g. AF)
2) Ventricular arrhythmias
What is the drug of choice for pharmacological cardioversion in patients with structural heart disease?
Amiodarone
Main indication of adenosine?
To terminate supraventricular tachycardias.
In AF, there is a subgroup of patients for whom a rhythm control strategy should be tried first (before rate control).
What are these exceptions?
1) Coexistent HF
2) First onset AF
3) Where there is an obvious reversible cause.
Is risk of falls sufficient reasoning to withold anticoagulation in AF?
No
When can new onset AF be considered for electrical cardioversion?
If within 48 hours of presentation
In cases of ischaemic stroke and atrial fibrillation, what is pharmacological management?
2 weeks of aspirin 300mg OD before consideration of lifelong anticoagulation.
Common contraindication of beta blockers in AF?
Asthma
What is the most likely cause of an irregular broad complex tachycardia in a stable patient?
Atrial fibrillation with bundle branch block
If a patient has been in AF for more than 48 hours then anticoagulation should be given for at least 3 weeks prior to cardioversion.
What is an alternative?
An alternative strategy is to perform a transoesophageal echo (TOE) to exclude a left atrial appendage (LAA) thrombus
If a patient has a new BP >= 180/120 mmHg AND retinal haemorrhage or papilloedema, what is next step?
Admit for specialist assessment
What is the 1st line anti-emetic for intracranial causes of N&V?
Cyclizine
Which chemo drug is most likely to cause hypomagnesaemia?
Cisplatin
In MSCC, should high dose steroids be given before or after urgent MRI?
High-dose oral dexamethasone should be given whilst awaiting investigations
What is the preferred analgesia in palliative patients with mild-moderate renal impairment?
Oxycodone
What is the preferred analgesia in patients with severe renal impairment?
Fentanyl/buprenorphine
What are some side effects of the chemo drug vincristine?
- peripheral neuropathy (reversible)
- paralytic ileus
