Section 03 · Monograph
Guanfacine
Reviewed Nov 2026FDA label
Tenex / IntunivAlpha-2A agonist
- Forms
- IR tab: 1, 2mg | ER tab: 1, 2, 3, 4mg
- Dose
- Tics (off-label): start 0.5-1mg qHS, titrate to 1-4mg/day divided
- MOA
- Selective α2A agonism in prefrontal cortex
Indications
- Hypertension (immediate-release)FDA-labeled
- ADHD (extended-release, Intuniv)FDA-labeled
Off-Label Uses
- Tic disorders including Tourette's syndromeOff-label
Mechanism of Action
- Selective alpha-2A adrenergic agonist acting in the prefrontal cortex, improving attention and potentially reducing tics
Full Dosing
Adult / usual
- Tics (off-label): start 0.5-1mg at bedtime; titrate to 1-4mg/day in divided doses
- Extended-release tablets should be swallowed whole; do not crush, chew or break
- Do not stop abruptly; taper in decrements of no more than 1mg every 3-7 days
Contraindications
- Known hypersensitivity to guanfacine
Drug Interactions
- Strong CYP3A4 inhibitors raise levels (reduce dose); inducers (carbamazepine, phenytoin) lower levels
- Additive sedation and hypotension with CNS depressants and antihypertensives
- Valproate levels may rise
Adverse Effects
- Somnolence, fatigue, headache
- Hypotension, bradycardia, syncope
- Dry mouth, abdominal pain
- Rebound hypertension on abrupt withdrawal
Monitoring Parameters
- Blood pressure and heart rate
- Sedation
- Withdrawal symptoms on dose changes
Pregnancy & Lactation
- Limited data; use if benefit justifies risk
- Unknown whether present in milk