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Bretylium tosylate
Bretylium tosylate (Bretylol)
Bretylium tosylate
(breh-TILL-ee-um TOZ-ill-ayt)
Pregnancy Category: C
Bretylate Parenteral (Rx)
Classification:
Antiarrhythmic, class III
Action/Kinetics:
Inhibits catecholamine release at nerve endings by decreasing excitability of the nerve terminal. Initially there is a release of norepinephrine, which may cause tachycardia and a rise in BP; this is followed by a blockade of release of catecholamines. Also increases the duration of the action potential and the effective refractory period, which may assist in reversing arrhythmias. Peak plasma concentration and effect: 1 hr after IM injection. Antifibrillatory effect within a few minutes after IV use. Suppression of ventricular tachycardia and ventricular arrhythmias takes 20-120 min, whereas suppression of PVCs does not occur for 6-9 hr. Therapeutic serum levels: 0.5-1.5 mcg/mL. t1/2: Approximately 5-10 hr. Duration: 6-8 hr. From 0% to 8% is protein bound. Up to 90% of drug is excreted unchanged in the urine after 24 hr.
Uses:
Life-threatening ventricular arrhythmias that have failed to respond to other antiarrhythmics. Prophylaxis and treatment of ventricular fibrillation. For short-term use only. Investigational: Second-line drug (after lidocaine) for advanced cardiac life support during CPR.
Contraindications:
Severe aortic stenosis, severe pulmonary hypertension.
Special Concerns:
Safety and efficacy in children have not been established. Dosage adjustment is required in clients with impaired renal function.
Side Effects:
CV: Hypotension (including postural hypotension), transient hypertension, increased frequency of PVCs, bradycardia, precipitation of anginal attacks, initial increase in arrhythmias, sensation of substernal pressure. GI: N&V; (especially after rapid IV administration), diarrhea, abdominal pain, hiccoughs. CNS: Vertigo, dizziness, lightheadedness, syncope, anxiety, paranoid psychosis, confusion, mood swings. Miscellaneous: Renal dysfunction, flushing, hyperthermia, SOB, nasal stuffiness, diaphoresis, conjunctivitis, erythematous macular rash, lethargy, generalized tenderness.
Overdose Management:
Symptoms: Marked hypertension followed by hypotension. Treatment: Treat hypertension with nitroprusside or another short-acting IV antihypertensive. Treat hypotension with appropriate fluid therapy and pressor agents such as norepinephrine or dopamine.
Drug Interactions:
- Digitoxin, Digoxin / Bretylium may aggravate toxicity due to initial release of norepinephrine
- Procainamide, Quinidine / Concomitant use
 inotropic effect of bretylium and  hypotension
How Supplied:
Injection: 50 mg/mL
Dosage
•IV
Ventricular fibrillation, hemodynamically unstable ventricular tachycardia.
Adults: 5 mg/kg of undiluted solution given rapidly. Can increase to 10 mg/kg if ventricular fibrillation persists; repeat as needed. Maintenance, IV infusion: 1-2 mg/min; or, 5-10 mg/kg q 6 hr of diluted drug infused over more than 8 min. Children: 5 mg/kg/dose IV followed by 10 mg/kg at 15-30-min intervals for a maximum total dose of 30 mg/kg; maintenance: 5-10 mg/kg q 6 hr.
Other ventricular arrhythmias.
•IV Infusion
5-10 mg/kg of diluted solution over more than 8 min. Maintenance: 5-10 mg/kg q 6 hr over a period of 8 min or more or 1-2 mg/min by continuous IV infusion. Children: 5-10 mg/kg/dose q 6 hr.
•IM
Other ventricular arrhythmias.
Adults: 5-10 mg/kg of undiluted solution followed, if necessary, by the same dose at 1-2-hr intervals; then, give same dosage q 6-8 hr. |
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