Guanfacine
Guanfacine (brand name Estulic, Tenex and the extended release Intuniv) is a sympatholytic drug used in the treatment of attention deficit hyperactivity disorder (ADHD) and hypertension (not to be confused with guaifenesin, an expectorant). It is a selective α2A receptor agonist. These receptors are concentrated heavily in the prefrontal cortex and the locus coeruleus, with the potential to improve attention resulting from interaction with receptors in the former. Guanfacine lowers both systolic and diastolic blood pressure by activating the central nervous system α2A norepinephrine autoreceptors, which results in reduced peripheral sympathetic outflow and thus a reduction in peripheral sympathetic tone.