Antidysrhythmic Agents Toxicity


Antidysrhythmic agents are classified via Vaughn-Williams into groups based on electrophysiologic properties (see Table 6.14). Toxicity is unique to each class.
 

Overview of Antidysrhythmic Agents
VAUGHN-WILLIAMS
CLASSIFICATION
MOA EXAMPLES SYMPTOMS OF TOXICITY TREATMENT
Class I Fast Na+ channel
blockers → stabilization of membranes.
IA:
Procainamide
Quinidine
Disorpyramide
IB:
Lidocaine
Phenytoin
IC:
Flecainide
Propafenone
Vary with agent
Agitation, confusion
Hypotension
Ventricular or brady-dysrhythmias
Supportive care
Activated charcoal
NaHCO3 for QRS widening
Class II Beta-Blocker      
Class III K Channel Blockers  → prolongation of repolorization.
Sotalol also has Beta-blocking activity.
Amiodarine
Sotolol
Vary with agen
Hypotension & bradycardia
QT Prolondation → VT, Vfib, torsades.

Chronic amiodarone therapy:
interstitial
pneumonitis, grey or
bluish skin changes,
corneal microdeposits
Supportive care
Activated charcoal
Gastric lavage (if early sotolol)
NaHCO3 for QRS widening
Class IV Calcium Channel Blocker