What is the recommended treatment and dosage for Attention Deficit Hyperactivity Disorder (ADHD) using Intuniv (guanfacine)?

Guanfacine (Intuniv) Treatment for ADHD

For ADHD treatment, extended-release guanfacine (Intuniv) is recommended at a dosage of 0.1 mg/kg once daily, with available tablet doses of 1,2,3, and 4 mg, administered preferably in the evening to minimize somnolence. 1

Medication Selection and Positioning

• Extended-release guanfacine is FDA-approved for ADHD treatment in children and adolescents aged 6-17 years 2
• Guanfacine is considered a second-line treatment after stimulants, with sufficient but less strong evidence compared to stimulants (which have an effect size of ~1.0 vs guanfacine's ~0.7) 3
• In Europe, guanfacine is only approved when stimulants are not suitable, not tolerated, or ineffective 1
• Guanfacine may also be used as adjunctive therapy with stimulant medications when stimulant therapy alone is not fully effective 3

Dosing and Administration

• Start with 1 mg daily, administered in the evening to minimize somnolence 1, 4
• Titrate doses to achieve maximum benefit with minimum adverse effects 3
• Available tablet doses are 1,2,3, and 4 mg 1
• The general dosing guideline is 0.1 mg/kg administered once daily 1
• Extended-release guanfacine is not substitutable on a mg-for-mg basis with immediate-release guanfacine due to different pharmacokinetics 2
• Treatment effects are not usually observed until 2-4 weeks after initiation, unlike stimulants which have a more rapid onset 1

Age-Specific Recommendations

• For elementary school-aged children (6-11 years): FDA-approved medications including extended-release guanfacine may be prescribed 3
• For adolescents (12-18 years): FDA-approved medications for ADHD with the assent of the adolescent should be prescribed 3
• Guanfacine is not recommended for preschool-aged children (4-5 years) as it has not received sufficient rigorous study in this population 3

Efficacy

• Recent meta-analysis shows guanfacine is significantly more effective than placebo in treating ADHD (Risk Ratio 1.78,95% CI: 1.59-2.01) 5
• Guanfacine has shown improved functional impairment and quality of life outcomes beyond core ADHD symptom control 1
• Studies show efficacy in reducing oppositional symptoms in children with ADHD and oppositional behavior 6

Safety and Monitoring

• Common adverse effects include:
  • Somnolence (38.6%), headaches (20.5%), and fatigue (15.2%) 5
  • Dry mouth, dizziness, irritability, and abdominal pain 3
• Cardiovascular effects require monitoring:
  • Decreased heart rate and blood pressure 3
  • Obtain personal and family cardiac history before starting 3
  • Consider ECG if risk factors are present 3
• Guanfacine should be tapered off rather than suddenly discontinued to prevent rebound hypertension 3
• Most adverse events are mild to moderate in severity and often occur during the dose-titration period 6

Special Considerations

• Guanfacine has higher specificity for alpha-2A receptors compared to clonidine, potentially resulting in fewer sedative effects 1
• Evening dosing is often preferred due to the common side effect of somnolence 1
• For adolescents with higher weight (>70-90 kg), they may exhibit lower clearance at steady-state than those with lower weight (≥30-50 kg) when given equivalent weight-based dosing 7
• Weight-adjusted doses >0.08 mg/kg but ≤0.12 mg/kg, if tolerated, may provide additional clinical benefits 7

Practical Dosing Algorithm

1. Start with 1 mg daily in the evening 1, 4
2. After 3-4 weeks, if response is inadequate, increase to 2 mg daily 4
3. Further dose increases should be made cautiously, as adverse reactions increase significantly with doses above 3 mg/day 4
4. Target dose should be approximately 0.1 mg/kg once daily 1
5. Monitor vital signs regularly, especially during dose adjustments 3
6. Allow 2-4 weeks to assess full treatment effect before making dose changes 1