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. t 1/2: 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.