Case report: guanfacine overdose

Intuniv (Guanfacine) 3 out of 5 stars Prolonged Bradycardia and Hypotension Following Guanfacine Extended Release Overdose. Walton J et al. J Child Adolesc Physcopharmacol 2014 Jul 10 [Epub ahead of print] Reference  Guanfacine is a central α2-agonist with a mechanism of action similar to that of clonidine. Originally marketed as an antihypertensive agent, it is now available as an extended-release preparation (Imtuniv) for treating children ages 6-17 with attention-deficit hyperactivity disorder (ADHD). It is thought the mechanism of action in that condition may involve stimulation of α2-receptors in the prefrontal cortex. As with clonidine, guanfacine can cause initial hypertension (from peripheral α-agonist activity) followed by prolonged bradycardia and hypotension (from central α2 effects. This short case report describes a 9-year-old boy with ADHD who was taking dexmethylphenidate and risperidone, as well as extended-release guanfacine (3 mg in the morning.) Inadvertently, the child received an extra dose of guanfacine-ER at around noon. Four hours later he was lethargic and drowsy but arousable. On arrival at hospital, he was bradycardic (40-50 bpm) and hypotensive (~80/40 mm Hg.) He was admitted for observation and given IV fluids. He recovered uneventfully over the next 24 hours. In their discussions, the authors suggest that — as illustrated by their case — a prolonged hypotensive response can follow even a mild overdose of guanfacine, and any overdose...
Source: The Poison Review - Category: Toxicology Authors: Tags: Medical ADHD attention deficit hyperactivity disorder clonidine guanfacine Source Type: news