Bretylium is a class III antiarrhythmic drug rarely used in modern medicine to treat ventricular tachycardia and ventricular fibrillation when first line agents fail.
The mechanism of action is the inhibition of norepinephrine release from nerve terminals and the blockade of potassium channels. Dramatic hypotension and bradycardia can occur with bretylium use. Bretylium is contraindicated if severe aortic stenosis or pulmonary hypertension is present as well as during digoxin toxicity.
Kowey PR, Levine JH, Herre JM, et al. Randomized, double-blind comparison of intravenous amiodarone and bretylium in the treatment of patients with recurrent, hemodynamically destabilizing ventricular tachycardia or fibrillation. The Intravenous Amiodarone Multicenter Investigators Group. Circulation 1995; 92:3255.