Bretylium Tosylate (Bretylol®)
Antidysrhythmic (Class III)
Bretylium is an adrenergic neuronal blocking agent that has both adrenergic and direct myocardial effects. Although the antidysrhythmic action of bretylium is poorly understood, like Lidocaine, it has been found to be effective in the treatment of ventricular fibrillation and ventricular tachycardia. Bretylium produces a prompt increase in ventricular fibrillation threshold, perhaps through postganglionic adrenergic blockade. At present, its use is reserved for those patients who fail to respond to lidocaine or other first-line antidysrhytmics.
Antifibrillatory effects are seen in 2-15 mintues following IV administration. Suppression of VT and other ventricular dysrhythmias occurs in 20 minutes or longer following IV administration.
2-6 hours (VF)
Up to 24 hours (VT)
VF and VT
None in the treatment of life-threatening conditions.
Hypotension in stable VT.
Bradycardia, heart block.
Vertigo, vomiting, dizziness, syncope, hypotension, bradycardia, increased PVCs, angina, transient hypertension and tachycardia lasting approximately 20 minutes.
Digoxin toxicity may be aggravated by the initial release of norepinephrine from bretylium.
50mg/ml in 10 ml vials.
5mg/kg rapid IV bolus (or single 500-mg bolus), repeat in 5 min at 10mg/kg (maximum dose 30-35 mg/kg). After conversoin, complete the loading dose of 5mg/kg and begin a continuous infusion at 1-2 mg/min. If VT persists, give a second dose of 5-10mg/kg in 10-30 minutes and every 6-8 hours as needed.
Dilute 500 mg (10 ml) to 50 ml, adminster 5-10 mg/kg IV over 8-10 minutes (max dose of 30 mg/kg).
Unknown efficacy.
Pregnancy Safety: unknown
Postural hypotension occurs in 50 % of patients receiving bretylium (keep them in supine position)
In VF, bretylium is usually only effective if followed by defibrillation.