Massive intravenous bolus bretylium tosylate

Area of Science:

• Pharmacology
• Cardiology
• Critical Care Medicine

Background:

• Bretylium tosylate is an antiarrhythmic agent used for ventricular tachycardia and fibrillation.
• High-dose intravenous administration requires careful hemodynamic monitoring.
• Understanding dose-dependent effects is crucial for patient safety.

Observation:

• A patient received a 30 mg/kg (2-gm) intravenous bolus of bretylium tosylate for recurrent ventricular arrhythmias.
• Following successful defibrillation, the patient experienced severe hypertension followed by prolonged hypotension.
• Ventricular ectopy ceased despite a critically low cardiac index.

Findings:

• The patient achieved a bretylium blood concentration of 8,800 ng/ml, the highest reported from a single bolus in humans.
• The case illustrates an exaggerated and severe hemodynamic response to a massive intravenous bretylium tosylate bolus.
• Refractory hypotension persisted despite the absence of further arrhythmias.

Implications:

• Massive intravenous bolus administration of bretylium tosylate can lead to dangerous hemodynamic instability.
• Clinicians should exercise extreme caution when considering high-dose bretylium, particularly via bolus injection.
• This case underscores the need for precise dosing and vigilant monitoring of cardiovascular parameters after bretylium administration.