guanfacine
n. a drug used for the treatment of hypertension. It acts as an agonist at alpha-adrenergic receptors, directly stimulating α2-adrenoreceptors to restrict the flow of impulses in peripheral sympathetic nerves supplying the arteries, thus causing them to relax (widen); most of the other commonly prescribed antihypertensive drugs act as beta blockers or as diuretics. Guanfacine is also a sedating agent used in the treatment of attention-deficit/hyperactivity disorder; it may, however, cause excess sedation and hypotension (low blood pressure). The drug has also been investigated for the management of posttraumatic stress disorder, Tourette’s disorder, and Alzheimer’s disease. U.S. trade names: Intuniv; Tenex.