Antiarrhythmic drugs exert a multiplicity of electrophysiologic actions
| Na+channel block (I1-150) | K+channel block (III) | Ca2+ channel block (IV) | β-blockade (II) | Other clinically important autonomic or electrophysiologic actions (all ✔✔) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| At all rates | Predominantly at fast rates | IKr | Other K+ channels | ||||||||||
| Adenosine | ✔? | IK-AChactivation | |||||||||||
| Amiodarone | ✔✔ | ✔ | ✔ | ✔✔ | Reduction of β receptor number (non-competitive β blockade), also a “class II” effect | ||||||||
| β Blockers | ✔✔ | ||||||||||||
| Bretylium | ✔? | ✔? | Inhibition of norepinephrine (noradrenaline) reuptake | ||||||||||
| Calcium channel blockers (verapamil, diltiazem) | ✔ | ✔✔ | |||||||||||
| Digitalis | Na+-K+ATPase inhibition; vagotonic actions | ||||||||||||
| Disopyramide | ✔✔ | ✔ | ✔? | anticholinergic effects | |||||||||
| Dofetilide | ✔✔ | ||||||||||||
| Flecainide | ✔✔ | ✔ | ✔ | ||||||||||
| Ibutilide | ✔✔ | Na+channel activation (also →↑QT) | |||||||||||
| Lidocaine | ✔✔ | ||||||||||||
| Mexiletine | ✔✔ | ||||||||||||
| Moricizine | ✔✔ | ||||||||||||
| Procainamide | ✔✔ | ✔ | ✔? | Ganglionic blockade | |||||||||
| Propafenone | ✔✔ | ✔ | ✔ | ✔ | |||||||||
| Quinidine | ✔✔ | ✔✔ | ✔ | α blockade; vagolytic | |||||||||
| Sotalol | ✔✔ | ✔ | ✔✔ | ||||||||||
| Tocainide | ✔✔ | ||||||||||||
✔✔ clinically important drug action.
✔ reported drug action that may contribute to clinical effects.
↵1-150 Roman numerals refer to the Vaughan Williams classification.