Bretylium
Class III
Mode of action
- increases action potential duration and refractory period of cardiac cells
- antifibrillatory effect on ventricular muscle - may be more important than class III effects in emergency treatment of malignant ventricular arrhythmias
- initially causes noradrenaline release and then produces the equivalent of a
sympathectomy, preventing noradrenaline release (class II effect)
Clinical use
- useful adjunct to DC shock in managing life-threatening ventricular
arrhythmias, especially refractory VF
- theoretical advantages of lignocaine but no advantage has been demonstrated clinically