Class Ib anti-arrhythmic drugs: ventricular actions and administration
THE CONTEXT
Class Ib drugs act predominantly in ventricular myocardium and include lidocaine and mexiletine.
Electrophysiology and uses
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Class Ib drugs shorten the action potential and the tissue refractory period.
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Their target channels are found predominantly in ventricular myocardium, explaining their use to treat or prevent ventricular tachycardia and ventricular fibrillation.
Individual drugs
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Lidocaine must be given intravenously and has a very short plasma half-life.
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Mexiletine can be given intravenously or orally but has many adverse effects.