Clonidine, sold under the brand names Catapres and Kapvay, among others, is an α2-adrenergic receptor agonist, hypotensive, sedative and anxiolytic drug used to treat high blood pressure, attention deficit hyperactivity disorder, perioperative pain, drug withdrawal, and menopausal flushing. Clonidine is sometimes prescribed off-label for tics. It is used orally, by injection, or as a transdermal skin patch. Onset of action is typically within an hour with the effects on blood pressure lasting for up to eight hours. Xylazine is a structural analog of clonidine.