Prescription non-stimulant medication approved in its extended-release form (Intuniv) for ADHD in children and adolescents aged 6–17. A selective alpha-2A adrenergic receptor agonist that strengthens prefrontal cortex function. Particularly effective for hyperactivity, impulsivity, and emotional dysregulation components of ADHD. Also used off-label for tic disorders, anxiety, and PTSD-related hyperarousal. Dosage must be determined by your prescribing physician.
Evidence rating moderate. Most-documented uses: adhd symptom improvement, reduced hyperactivity and impulsivity, emotional regulation improvement. 10 sources indexed (2023–2025), with 1 interaction record on file.
The science
How it works, mechanistically.
Core mechanism
Selectively stimulates postsynaptic alpha-2A adrenergic receptors in the prefrontal cortex, strengthening prefrontal network connectivity and improving working memory, attention regulation, and behavioral inhibition. Unlike clonidine, guanfacine has 15–25 times greater selectivity for alpha-2A over alpha-2B and alpha-2C receptors, resulting in less sedation and hypotension.
Class
Non-Stimulant ADHD Medication
Dosing
Dosing & protocol.
Common range
1–4 mg daily for extended-release; 0.5–2 mg daily for immediate-release (as prescribed by your physician)
Recommended form
Extended-release tablet (Intuniv) or immediate-release tablet (Tenex)
Do not take extended-release tablets with high-fat meals (increases absorption variability). Do not crush, chew, or break extended-release tablets. Taper gradually when discontinuing to avoid rebound hypertension.
Guanfacine lowers sympathetic outflow and commonly causes sedation, fatigue, dizziness, bradycardia, and lower blood pressure. Alcohol can add CNS depression and worsen dizziness, slowed reaction time, orthostatic symptoms, and fainting risk. The combination is most concerning when starting guanfacine, increasing the dose, drinking heavily, or using other sedating substances.
Recommendation: Avoid alcohol when starting guanfacine or after any dose increase. If you drink later in stable treatment, keep intake low and avoid driving, heat exposure, or standing quickly. Seek medical help for fainting, severe dizziness, very slow pulse, confusion, or repeated vomiting.
Yu S, Shen S, Tao M. Guanfacine for the Treatment of Attention-Deficit Hyperactivity Disorder: An Updated Systematic Review and Meta-Analysis. Journal of child and adolescent psychopharmacology. 2023
Singh D, Silver M, Jacob T. A Randomized Double-Blind Placebo-Controlled Trial of Guanfacine Extended Release for Aggression and Self-Injurious Behavior Associated With Prader-Willi Syndrome. American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. 2025
Yükcü B, Önal BS, Çobanoğlu Osmanlı C et al.. Cardiological Findings in Children and Adolescents Before and After Guanfacine Treatment for Attention Deficit and Hyperactivity Disorder. Children (Basel, Switzerland). 2025
Pattamin N, Phongphithakchai A, Spano S et al.. Efficacy and safety of guanfacine in hospitalized patients with delirium: A scoping review. Critical care and resuscitation : journal of the Australasian Academy of Critical Care Medicine. 2024
Okamoto LE, Urechie V, Rigo S et al.. Hyperadrenergic Postural Tachycardia Syndrome: Clinical Biomarkers and Response to Guanfacine. Hypertension (Dallas, Tex. : 1979). 2024
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