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antiarrhythmic agent, Group IB
Indications:
- treatment of ventricular arrhythmias [2]
Mechanism of action:
- class Ib antiarrhythmic agents shorten both the action potential duration & refractoriness at high concentrations
- thus class Ib agents possess local anesthetic & membrane stabilizing properties characteristic of all class I agents
- class Ib agents have less of an effect on inhibition of Na+ influx during phase 0 of the fast sodium channel action potential than do class 1a agents or class 1c agents
- class Ib agents slow conduction in diseased tissue & shorten repolarization [2]
- proarrhythmic effects are less common with class Ib agents than with class Ia agents or class III agents
Interactions
drug interactions
Specific
Lidocaine Parenteral
mexiletine (Mexitil)
moricizine (Ethmozine)
phenytoin; diphenylhydantoin; PTN (Dilantin, Dephenylan, Antilepsin)
tocainide (Tonocard, Taquidil)
General
antiarrhythmic agent, Group I
References
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 150, 155
- Medical Knowledge Self Assessment Program (MKSAP) 15, 16.
American College of Physicians, Philadelphia 2009, 2012