Bretylol
Class
Antidysrhythmic (class 111)
Description
Bretylol 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 treating
ventricular fibrillation and ventricular tachycardia. Bretylol produces a prompt
increase in ventricular fibrillation threshold, perhaps through postganglionic
adrenergic blockade. It causes an initial release of norepinephrine from
postganglionic nerve terminals. At present, its use is reserved for patients who
fail to respond to lidocaine or other first-line antidysrhythmics.
Onset & Duration
Onset: Antifibrillatory effects are seen in 2-15 min. after IV administration.
The
suppression of ventricular tachycardia and other ventricular dysrhythmias occurs
in 20 min. or longer after IV administration.
Duration: 2-6 hr (ventricular fibrillation). Up to 24 hr (ventricular
tachycardia).
Indications
Treatment of VF and VT refractory to lidocaine.
Contraindications
None in the treatment of life-threatening dysrhythmias
Adverse Reactions
1. Vertigo
2. Nausea and vomiting
3. Dizziness
4. Syncope
5. Hypotension
6. Bradycardia
7. increase in PVCs
8. Angina pectoris
Drug Interactions
Digoxin toxicity may be aggravated by the initial release of norepinephrine from
bretylium.
Special Considerations
1. Pregnancy safety: Category C
2. Postural hypotension occurs in 50% of patients receiving Bretylium (patients
should be kept in supine position).
3. In ventricular fibrillation, bretylium is usually only effective if followed
by defibrillation.
4. Ventricular tachycardia does not respond to bretylium as rapidly as
ventricular fibrillation.
Note: Feel free to discuss this medication and your experiences in administering it in an emergency or hospital based setting on our message board
