1/9: Arrhythmia Drugs Flashcards Preview

BNF: Cardiovascular System > 1/9: Arrhythmia Drugs > Flashcards

Flashcards in 1/9: Arrhythmia Drugs Deck (27)
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State the Anti-Arrhythmic Drugs Within Class 1 - 4 

  1. Lidocaine + Flecanide
  2. Beta Blockers
  3. Amiodarone / Sotalol
  4. CCB (Verapamil)



True or False? "hyperkalaemia exposes people to digitalis toxicity"

False - HypoKalemia does


The Likelohood of toxicity increases progressively through what range of digoxin level?

1.3-3mcg/ litre of blood


What is the MHRA Warding with Sotalol

It May Prolong QT. Correct Hypomagnesium + Hypokalemia before initiaing.


Which two drug classes are first line for rate control in AF?

1.. Beta Blocker

2.. Rate Limiting Calcium Channel Blocker


Give 2 examples of Rate Limiting CCBs , and state their Class and MOA

Verapamil  and Diltiazem. They are Non-Dihydroprydines and thus are more selective for  the calcium channel blockers in the heart. Between the two, Verapamil is the most cardioselective, so its okay in athsma. 


State the first-line diagnostic agent in Supraventricular Tachycardia, list its MOA and Interactions and Cautions

Drug: Adenosine

MOA: It is an Agonist of the G protein coupled receptors and slows the heart muscle down, increasing the refractoryness of the AV node and breaking re-entry circuits.

Cautions: By interfering with AV and SA nodes, can cause bradycardia.  It can also cause bronchospasm so avoid in Asthma or COPD. Avoid in Decompensated HF

Interactions: Dipyriamidole blocks cellular updake of Adenosine, This increases its effects. Caffine can reduce its effect, so patients may need higher doses 


Can the GP initiate amiodarone

Nope, specialist care only within hospitals


What is the loading dose of amiodarone?

Week 1: 200mg TDS

Week 2: 200mg BD

Week 3 and thereafter 200mg OD


What are the 6 toxicities of Amiodarone

Amiodarone can precipitate:

1 Corneal Microdeposits (Drivers may be dazzled by lights)

2 Thyroid (AmIODarone) So both Hypo or Hyperthyroidism

3 Pulmonary Toxicity or Pneumonitis

4 Liver Toxicity (Hepatocellulatr) 

5 Peripheral Neuropathy (Numbness or Tingling) 

6 Phototoxicity (Grey discolouration of skin)



What should happen when a patient is taking amiodarone gets thyrotoxicosis?

Withdraw amiodarone (at least temporarily) to help achieve control


What are the Main monitoring points for Amiodarone?

1. Thyroid function before treatment then every 6 months (TSH, T4 and T3)
2. LFTs before starting then every 6 months 
3. Chest X-ray before starting 
4. Serum potassium before starting


Councelling for Amiodarone?

  1. Shield skin from light during treatment and for several months after discontinuing
  2. Watch out for Weight Loss/ Gain
  3. Persistent cough / Breathlessness
  4. Do not drink grapefruit juice (can increase risk of side effects)


Which beta-blocker may prolong QT and cause potentially life-threatning arrhythmias?



Antidote to Digoxin?

Digoxin-Specific Antibiody. Digifab 


When a Patient is on Digoxin, what must be the ventricular rate at rest ?



"A Digoxin LD is needed for patients who have heart failure and are in sinus rhythm" True or False?

False -- it is not needed here


What is the most important  determinant of dosage for digoxin?

Renal Function


Give the MOA / Cautions/ Side Effects of Digoxin

Digoxin is Negatively Chronotropic and Positively Inotropic. In AF it increases Parasympathetic Vagal Tone. 

In HF it blocks Ca2+ escape, so it accumulates within the myocyte. Naaccumulates also because the Ca/K/NA channel is blocked. This explains its reduction of rate.

Side effects: Digoxin can cause Blurred or Yellow vision, Bradycardia, Rash, GI disturbance & Dizziness

Cautions: Reduce dose in renal failure, heart block. Hypokalaemia Hypomagnamesia and Hypercalcaemia predispose the risk of digoxin toxicity.


When digoxin is given concomitantly with amiodarone, dronedarone and quinine, what should be done to the dose?

half the dose


Important Interactions with Digoxin?

Digoxin Interacts with loop + thiazide diuretics, which INCREASE the risk of digoxin toxicity by causing hypokalaemia. 

Amiodarone / CCB / Quinine / Spironolactone can all increase the [digoxin] so reduce or half the dose of digoxin


Dose of Digoxin in Heart Failure and Dose o f Digoxinin AF?

AF: Maintenance 125–250 micrograms daily, dose according to renal function and initial loading dose, reduce dose in the elderly.

HF for adults in sinus rhythm:  62.5–125 micrograms once daily, reduce dose in the elderly.



Key Monitoring for Digoxin?

Symptoms and HR, Check ECG /Electrolytes and Renal Functionality espacially during illness.


What is the dose of Dabigatran / Apixaban / Edoxaban / Rivaroxaban in Non Valvular AF?

Dabigatran: 150mg twice daily

Apixaban: 5mg twice daily 

Edoxaban: 60mg once daily



Give the Mechanism of Action of Amiodarone

Amiodarone causes Blockade of Sodium, Calcium and Potassium channels, and antagonism of σ and ß adrenergic receptors. These effects reduce spontaneous depolarisation (automaticity) and increase resistance depolarisation (refractoriness). It also increases the chance of conversion to Sinus rhythm.



List all possible indications for Aspirin

Acute Coronary Syndrome (ACS), Acute Ischaemic Stroke. Cardiovascular, Cerebrovascular or Peripheral Arterial Disease.