propranolol
n. a beta blocker used primarily to treat hypertension. In low doses, it is used as an adjunctive agent in the treatment of certain forms of social phobia, such as fear of public speaking or performance, predominantly due to its ability to control certain peripheral symptoms of anxiety, such as tremor and vocal quavering. Because it produces a nonspecific blockade of beta-adrenergic receptors, it should not be taken by individuals with asthma or reactive airway disease, due to its ability to constrict bronchial smooth musculature and thereby induce breathing difficulties. U.S. trade name: Inderal.