What is the recommended initial dose of guanfacine (Intuniv extended‑release and Tenex immediate‑release) for treating attention‑deficit/hyperactivity disorder in children/adolescents and adults?

Starting Dose of Guanfacine for ADHD

Start guanfacine extended-release at 1 mg once daily, administered in the evening, and titrate upward by 1 mg per week based on clinical response and tolerability, targeting a weight-adjusted dose of 0.05-0.12 mg/kg/day (maximum 4-7 mg/day). 1, 2

Initial Dosing Protocol

• Begin with 1 mg once daily for both children/adolescents (ages 6-17 years) and adults, regardless of body weight 1, 2
• Evening administration is strongly preferred because somnolence and fatigue are the most common adverse effects, and nighttime dosing minimizes daytime sedation that could interfere with school or work performance 1, 3
• Morning administration is equally effective if evening dosing causes practical difficulties, though tolerability may be reduced 3

Titration Schedule

• Increase by 1 mg per week based on symptom response and adverse effect tolerability 1, 2
• Target dose range is 0.05-0.12 mg/kg/day, which translates to 1-7 mg/day depending on body weight 1, 2
• Most patients respond optimally between 2-4 mg/day, though some adolescents and adults may require higher doses 1, 4
• Maximum approved dose is 4 mg/day in most clinical contexts, though doses up to 7 mg/day have been studied and used 1, 2, 5

Critical Timing Expectations

• Therapeutic effects require 2-4 weeks to emerge, unlike stimulants which work immediately 1
• Counsel patients and families explicitly that guanfacine is not a rapid-acting medication, and premature discontinuation due to perceived lack of efficacy is a common pitfall 1
• Sustained improvements over 24 months have been demonstrated in open-label extension trials 1, 4

Pre-Treatment Assessment

• Obtain baseline blood pressure and heart rate before initiating guanfacine, as the medication causes modest decreases (1-4 mmHg BP, 1-2 bpm HR) 1
• Screen for personal and family cardiac history, including Wolf-Parkinson-White syndrome, unexplained syncope, sudden cardiac death, hypertrophic cardiomyopathy, and long QT syndrome 1
• Consider ECG if cardiac risk factors are present, though routine ECG is not required for all patients 2

Monitoring During Titration

• Check blood pressure and heart rate at each dose adjustment and periodically during maintenance therapy 1
• Monitor ADHD symptoms systematically using parent and teacher reports (e.g., ADHD-RS-IV) at each dose change 1
• Watch for excessive somnolence, hypotension, or bradycardia, particularly during the first 2-4 weeks and with each dose increase 1, 4

Available Formulations

• Extended-release tablets are available in 1,2,3, and 4 mg strengths 2
• Tablets should be swallowed whole; if a patient cannot swallow tablets, discuss with pharmacy about appropriate liquid formulations or switching to immediate-release guanfacine with adjusted dosing schedules 1

Position in Treatment Algorithm

• Guanfacine is generally second-line after stimulants due to smaller effect sizes (approximately 0.7 vs 1.0 for stimulants) 1, 2
• Consider guanfacine as first-line when ADHD co-occurs with:
  • Sleep disturbances (guanfacine improves sleep onset when given at bedtime) 1
  • Tic disorders (guanfacine treats both conditions without worsening tics) 1
  • Substance use risk (guanfacine is non-controlled) 1
  • Stimulant intolerance or contraindications 1

Common Pitfalls to Avoid

• Never start at doses higher than 1 mg, even in heavier adolescents or adults, as this increases risk of hypotension and excessive sedation 1, 2
• Never abruptly discontinue guanfacine—taper by 1 mg every 3-7 days to prevent rebound hypertension 1
• Do not expect immediate symptom improvement—allow at least 2-4 weeks at target dose before concluding treatment failure 1
• Avoid combining with clonidine, as both are alpha-2 agonists and would increase sedation and cardiovascular effects without clear evidence of superior efficacy 1

Special Population Considerations

• Not approved for children under 6 years of age; behavioral therapy is first-line for preschoolers, and dextroamphetamine is the only FDA-approved medication for ages 4-5 years 1
• Use with extreme caution in pregnancy due to limited safety data showing 20% low birth weight rate in one small study; methylphenidate or amphetamines are preferred if medication is necessary 6
• No published breastfeeding data exist for guanfacine 2, 6

Adjunctive Use with Stimulants

• Guanfacine extended-release is FDA-approved for adjunctive therapy with stimulants, allowing for lower stimulant doses while maintaining efficacy and potentially reducing stimulant-related adverse effects 1
• Monitor for opposing cardiovascular effects when combining with stimulants, as stimulants increase heart rate and blood pressure while guanfacine decreases both 1