Antiarrhythmic

Front 1

Adenosine

Back 1

• Mechanism: works on adenosine receptors → ↓ conduction through AV node, ↑ refractory period of AV node
• Administration: iv
• Metabolism: Very short t1/2
• Adverse Effects:
o Heart block
o Asystole (transient or prolonged)
o Headache, flushing
o Hypotension
o Arrhythmia
• Drug interactions
o Methylxanthine ie caffine (may ↓ effect of adenosine)
o Dipyridamole (may ↑ Adenosine effect)

Front 2

Amiodarone (a mee’oh da rone)

Back 2

• Class 3 antiarrhythmic drug
• Delay repolarization (↑ refractory period) – mostly by K+ channel block
o Blocks K channels (↑ AP)
o Na channel blockage (class 1)
o Ca channel blockage (class 4)
• Administration: oral or iv
• Other Effects:
o Adrenergic block (class 2)
• Metabolism: hepatic; t1/2 = weeks
• 2 iodine atoms – hypo- or hyperthyroidism

Front 3

Adverse Effects of Amiodarone & drug interactions:

Back 3

o Heart:
• ↓ HR; AV block
• ↑ QT (early afterdepolarization; torsades de pointe)
o Thyroid: ↑ or ↓
o Eye: Corneal deposits; ↓ visual acuity
o Skin: photosensitivity; blue-gray discoloration
o Lung: Pulmonary fibrosis
o Liver: abnormal tests
o Neuro: peripheral neuropathy
o Interactions:
• Decreased elimination of: digoxin, warfarin

Front 4

Diltiazen (dil tye’ a zem)

Back 4

• Class 4 antiarrhythmic drug: Ca Channel Blockers
o Low Vascular Selectivity (major effect on heart)
• Use: Atrial Fibrillation
• Effects: ↓ conduction velocity → ↑ ERP in AV node
• Other effects:
o Vasodilation
o ↓ myocardial contractility
• Adverse Effects:
o Hypotension
o ↓ contractility
o Heart Block

Front 5

Disopyramide (dye soe peer a mide)

Back 5

• Effects:
o ↓ conduction velocity
o ↑ refractory period
• Other Effects:
o anti-vagal
• Anticholinergic side-effects
• ↓ myocardial contractility – issue in HF
• Elimination: Liver & Urine
• Adverse Effects:
o Cardiac (↑ QT → ↑ risk early after-depolaration (torsade de pointe)
• ↑↑↑ risk arrhythmias (↑ QT interval)
o GI (constipation – anticholinergic effect)

Front 6

Dofetilide (doe fet’ il ide)

Back 6

• Class 3 antiarrhythmic
• Used in A Fib
o ↑ AP duration (K channel block)
• Administration: oral
• Metabolism: renal > hepatic
• Adverse Effects: proarrhythmic (restricted use)

Front 7

Dronedarone (droe’ ne’ da rone)

Back 7

• Class 3 (but characteristics of all classes)
• Newer Amiodarone analog that lacks iodine atoms
• Metabolism: liver, but shorter t1/2 than amiodarone
• Adverse Effects:
o HF warning
o Diarrhea, nausea, and vomiting
o ↑ QT interval → arrhythmias
o fetal harm possible
o drug interactions:

Front 8

Esmolol

Back 8

• Class 2 antiarrhythmic
• β1 >>>β2

Front 9

Flecainide (flek’ a nide)

Back 9

• Class IC
o Blocks Na channels
o No effect on AP duration
o ↓ myocardial contractility (issue in HF)
• Adverse Effects:
o Blurred vision
o Worsening HF
o Arrhythmias

Front 10

Ibutilide

Back 10

• Class 3 antiarrhythmic
• Used in A Fib
o ↑ AP duration (K channel block)
• Administration: iv
• Metabolism: hepatic
• Adverse Effects: proarrhythmic

Front 11

Lidocaine (lye’ doe kane)

Back 11

• Class IIB antiarrhythmic
• Effect: ↓ conduction in depolarized cells (especially partially depolarized cells – ischemic cells)
• Administration: iv
o Significant 1st pass metabolism
• Clearance ↓ by: (less flow to liver = less clearance)
o Liver dz
o HF
o Propranolol (↓’s CO)
• Adverse Effects:
o Cardiac: Not as cardiotoxic as others
o Neuro: tremors, lightheaded, seizures

Front 12

Mexiletine (mex il’ e teen)

Back 12

• Oral
• Analog similar to Lidocaine

Front 13

Quinidine

Back 13

• Use: arrhythmias, atria fibrillation
• Effects:
o ↓ conduction velocity
o ↑ refractory period
• Other Effects:
o α-blockade
o anti-vagal (in some can cause tachycardia)
• Elimination: Liver

Front 14

Quinidine Adverse Effects:

Back 14

o Cardiac (↑ QT → ↑ risk early after-depolaration (torsade de pointe)
• ↑↑↑ risk arrhythmias (↑ QT interval)
o GI (diarrhea – common) – counterintuitive
o Neuro (headache, tinnitis)
o Hypersensetivity Reactions (↓ Plt, hepatotoxicity)

Front 15

Quinidine Drug Interactions:

Back 15

• Drug Interactions:
o Quinidine + digoxin → ↑ digoxin levels
o Quinidine + phenytoin or Phenobarbital → ↓ quinidine level
o Quinidine can inhibit Cyp2D6

Front 16

Procainamide (proe kane’ a mide)

Back 16

• Effects:
o ↓ conduction velocity
o ↑ refractory period
• Elimination: urine; Liver (N-acetyl-procainamide (active drug) → urine)
o Monitor blood levels of both
• Adverse Effects:
o Cardiac (torsades de pointe)
• Hypotension
o Drug-induced lupus (reversible) – Slow acetylator phenotype
o agranulocytosis

Front 17

Propafenone (proe pa feen’ none)

Back 17

• Class IC
o Blocks Na channels
o Some β-blockage → ↓ contractility & HR
o ↓ myocardial contractility (issue in HF)
• Adverse Effects:
o Worsening HF
o Pro-Arrhythmias

Front 18

Propranolol

Back 18

• Class 2 antiarrhythmic drug

Front 19

Satolol (soe’ ta lole)

Back 19

• Class 3 antiarrhythmic
• Racemic mixture:
o Block K+ Channels (↑ AP duration; ↑ QT interval)
o β-block activity of L-isomer (↓ conduction AV node)
• Adverse Effects:
o Worsening HF (β-Blocker effects)
o Pro-arrhythmic (torsades de pointes)

Front 20

Verapamil (ver ap’ a mil)

Back 20

• Class 4 antiarrhythmic drug: Ca Channel Blockers
o Low Vascular Selectivity (major effect on heart)
• Use: Atrial Fibrillation
• Effects: ↓ conduction velocity → ↑ ERP in AV node
• Other effects:
o Vasodilation
o ↓ myocardial contractility
• Adverse Effects:
o Hypotension
o ↓ contractility
o Heart Block