About Propranolol A synthetic non-selective beta blocker , Antiarrhythmic,antihypertensive,antianxiety,migraine prophylatic. Mechanism of Action of Propranolol Propranolol is a non selective beta receptor antagonist. It have negative chronotropic and negative inotropic effects on heart. It decreases oxygen consumption- cardiac work and aortic pressure It decreases nor adrenaline and renin releases. It decreases central sympathetic out flow. In sympathetic over activity, it prolongs systole by retarding conduction. It increases oxygen supply and exercise tolerance in angina patients. It decrease automaticity and abbreviates refractory period of myocardial fibers and decreases rate of depolarization in SA node, Purkinje fibers, and other ectoptic foci. Prolong effective refractory period of AV node and AV conduction is delayed. At higher doses direct depressant membrane stabilizing action is exerted.