Drugs CCC

Question 1

What class of drug is amiodarone?

Answer 1

Class III anti-arrhythmic medications

Question 2

Indications of amiodarone?

Answer 2

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)

Question 3

Mechanism of amiodarone?

Answer 3

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.

Question 4

How does amiodarone work in AF?

Answer 4

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

Question 5

Half life of amiodarone?

What does this mean?

Answer 5

58 days –> loading dose is often required

Question 6

Side effects of amiodarone?

Answer 6

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

Question 7

Contraindications of amiodarone?

Answer 7

1) Severe hypotension

2) Heart block (except in cardiac arrest)

3) Active thyroid disease (thyrotoxicosis, hyperthyroidism, hypothyroidism)

4) Iodine sensitivity

Question 8

How can amiodarone affect the thyroid?

Answer 8

Amiodarone can lead to both hypothyroidism (amiodarone-induced hypothyroidism) and less commonly hyperthyroidism (amiodarone-induced thyrotoxicosis).

Question 9

What blood tests are needed for amiodarone monitoring?

Answer 9

• TFTs
• U&Es
• LFTs

Question 10

Amiodarone can increase the conc of what 3 drugs?

Answer 10

1) Digoxin
2) Diltiazem
3) Verapamil

This may increase risk of bradycardia, AV block and HF

Question 11

Indications for flecainide?

Answer 11

1) Rhythm control (pharmacological cardioversion) in supraventricular tachycardia (e.g. AF)

2) Ventricular arrhythmias

Question 12

What is the drug of choice for pharmacological cardioversion in patients with structural heart disease?

Answer 12

Amiodarone

Question 13

Main indication of adenosine?

Answer 13

To terminate supraventricular tachycardias.

Question 14

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?

Answer 14

1) Coexistent HF
2) First onset AF
3) Where there is an obvious reversible cause.

Question 15

Is risk of falls sufficient reasoning to withold anticoagulation in AF?

Answer 15

No

Question 16

When can new onset AF be considered for electrical cardioversion?

Answer 16

If within 48 hours of presentation

Question 17

In cases of ischaemic stroke and atrial fibrillation, what is pharmacological management?

Answer 17

2 weeks of aspirin 300mg OD before consideration of lifelong anticoagulation.

Question 18

Common contraindication of beta blockers in AF?

Answer 18

Asthma

Question 19

What is the most likely cause of an irregular broad complex tachycardia in a stable patient?

Answer 19

Atrial fibrillation with bundle branch block

Question 20

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?

Answer 20

An alternative strategy is to perform a transoesophageal echo (TOE) to exclude a left atrial appendage (LAA) thrombus

Question 21

If a patient has a new BP >= 180/120 mmHg AND retinal haemorrhage or papilloedema, what is next step?

Answer 21

Admit for specialist assessment

Question 22

What is the 1st line anti-emetic for intracranial causes of N&V?

Answer 22

Cyclizine

Question 23

Which chemo drug is most likely to cause hypomagnesaemia?

Answer 23

Cisplatin

Question 24

In MSCC, should high dose steroids be given before or after urgent MRI?

Answer 24

High-dose oral dexamethasone should be given whilst awaiting investigations

Question 25

What is the preferred analgesia in palliative patients with mild-moderate renal impairment?

Answer 25

Oxycodone

Question 26

What is the preferred analgesia in patients with severe renal impairment?

Answer 26

Fentanyl/buprenorphine

Question 27

What are some side effects of the chemo drug vincristine?

Answer 27

• peripheral neuropathy (reversible)
• paralytic ileus