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Bretylium is an adrenergic neuron blocker used as antiarrhythmic drug (class III). It prolongs the duration of ventricular action potential, thus used in treatment of ventricular fibrillation.

The effective refractory period of ischemic heart tissue is shortened which becomes more excitable, leading to rhythm disturbance. This drug is more effective in ischemic tissue as it prolongs the refractory period and is used in conditions where lignocaine and defibrillation have failed.

Mechanism of Action:

a. Has MSA (decreases release of NE)

b. Blocks K+ channels increasing duration of action potential and refractory period (blocks re-entry circuits)


Given by oral route and having a half life of about 9 hours.

  1. Anti-arrhythmic
  2. Antihypertensive
Adverse effects

Postural hypotension



Treatment of Ventricular Fibrillation
  1. Electrical defibrillation
  2. Lignocaine
  3. Bretylium
  4. Amidorone
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