What is the recommended dosing of Intuniv (guanfacine) for adults with Attention Deficit Hyperactivity Disorder (ADHD)?

Adult Dosing of Intuniv (Guanfacine Extended-Release) for ADHD

Intuniv is not FDA-approved for adults with ADHD, and the evidence for adult dosing is limited to off-label use based on pediatric guidelines and a single long-term adult study. 1, 2

FDA-Approved Dosing (Hypertension in Adults)

The FDA label for immediate-release guanfacine in adults specifies:

• Initial dose: 1 mg daily at bedtime 1
• Titration: May increase to 2 mg after 3-4 weeks if needed 1
• Maximum dose: 3 mg/day (adverse reactions increase significantly above this dose) 1

Off-Label Extended-Release Dosing for Adult ADHD

Based on the only published long-term adult ADHD study and extrapolation from pediatric guidelines:

Starting dose: 2 mg once daily 2

Maintenance dose: 4-6 mg once daily 2

Titration schedule:

• Start at 2 mg/day 2
• Increase by 1 mg per week based on response and tolerability 3, 4
• Target range: 4-6 mg/day for adults 2
• Maximum studied dose in adults: 6 mg/day 2

Timing of Administration

Evening dosing is strongly preferred to minimize daytime somnolence and fatigue, which are the most common adverse effects occurring in 38.6% of patients 3, 5

Critical Safety Monitoring

Baseline assessment required:

• Blood pressure and heart rate 3, 4
• Personal and family cardiac history 4

Ongoing monitoring during dose adjustments:

• Blood pressure and heart rate at each titration 3, 4
• ADHD symptoms at each dose change 3

Expected Timeline for Response

Clinical benefits typically require 2-4 weeks at an optimized dose, unlike stimulants which work immediately 3, 4

Discontinuation Protocol

Never abruptly stop guanfacine—taper by 1 mg every 3-7 days to avoid rebound hypertension 3, 4, 1

Common Adverse Effects in Adults

The adult study showed 94.2% experienced at least one treatment-emergent adverse event, with most being mild to moderate 2:

• Somnolence (most common) 5, 2
• Thirst 2
• Decreased blood pressure 2
• Postural dizziness 2
• Bradycardia 2
• Constipation 2
• Headache (20.5%) 3, 5
• Fatigue (15.2%) 3, 5

Important Clinical Caveats

Guanfacine is a second-line treatment with smaller effect sizes (0.7) compared to stimulants (1.0) 3, 4

The evidence base for adults is weak—only one open-label extension study exists, with stronger evidence limited to children 5, 2

Consider guanfacine in adults when:

• Stimulants are contraindicated, not tolerated, or ineffective 3, 4
• Substance use disorder is present (non-controlled medication) 3
• As adjunctive therapy to stimulants for partial responders 3, 6

Discontinuation rate due to adverse events was 19.9% in the adult study, indicating tolerability concerns 2