Propranolol (Inderal®) is a non-selective beta blocker (i.e. it blocks the action of adrenalin on both β1- and β2-adrenoreceptors). It has various uses, such as treatment of high blood pressure, prophylaxis of migraine, controlling tremors, suppressing the symptoms of hyperthyroidism (tachycardia, tremor), lowering portal pressure in portal hypertension when this has led to esophageal varices, as well as in the management of anxiety and panic disorders.
Propranolol, acting as a beta-blocker, has also been shown to have an effect on the formation of memories with strong emotional content. During very emotional or traumatic times, adrenaline and noradrenaline are released from the adrenal medulla which activate beta receptors in the brain. The effect is to give the associated memories more "force" due to the strong emotional content and subsequent beta-receptor activation. Propranolol blocks beta-receptor action, and thereby reduces or eliminates the emotional component of the memory. The effect is to make the memory more mundane.
References