Ventricular tachycardia bretylium

Pharmacology Bretylium tosylate inhibits norepinephrine release by depressing adrenergic nerve terminal excitability, inducing a chemical sympathectomy-like state. Bretylium blocks the release of norepinephrine in response to neuron stimulation. Peripheral adrenergic blockade causes orthostatic hypotension but has less effect on supine blood pressure. It has a positive inotropic effect on the myocardium. Pharmacokinetics Peak plasma concentration and peak hypotensive effects are seen within 1 hour of IM administration. However, suppression of premature ventricular beats is not maximal until 6 to 9 hours after dosing, when mean plasma concentration declines to less than 50% of peak level. Antifibrillatory effects occur within minutes of an IV injection. Suppression of ventricular tachycardia and other ventricular arrhythmias develops more slowly, usually 20 minutes to 2 hours after parenteral administration. 

Bretylium tosylate is frequently used in the treatment of ventricular arrhythmias which are refractory to other anti-arrhythmic drugs. It is specifically useful in the diagnosis of ventricular tachycardia. 

Therapeutic uses Bretylium is reserved for life-threatening ventricular arrhythmias, especially recurrent ventricular fibrillation or tachycardia. 

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