Intuniv Dosage for Adults
Intuniv (guanfacine extended-release) is not FDA-approved for adults and has limited efficacy data in this population; however, when used off-label for ADHD in adults, the recommended starting dose is 1 mg once daily, titrated by 1 mg weekly to a target range of 1-7 mg/day (0.05-0.12 mg/kg/day). 1
FDA-Approved Dosing Context
- The FDA-approved indication for guanfacine tablets is hypertension in adults, with a starting dose of 1 mg daily at bedtime, potentially increasing to 2 mg after 3-4 weeks if needed, though most antihypertensive effect occurs at 1 mg 2
- Doses above 3 mg/day significantly increase adverse reactions in the hypertension indication 2
- Intuniv XR is only approved in Canada for children and adolescents aged 6-17 years for ADHD, not for adults 1
Off-Label ADHD Dosing in Adults
When guanfacine is considered for ADHD treatment in adults (off-label use):
- Start with 1 mg once daily 1
- Titrate by 1 mg per week based on response and tolerability 1
- Target dose range: 1-7 mg/day or 0.05-0.12 mg/kg/day 1
- Evening or bedtime administration is preferable to minimize sedation 3
Critical Clinical Considerations
Important caveats about adult use:
- There is very limited published data on guanfacine's efficacy for ADHD in adults, and alternative agents are generally preferred 1
- Guanfacine should only be considered after a thorough risk-benefit discussion acknowledging the limited adult efficacy data 1
- The medication has a delayed onset of 2-4 weeks before clinical benefits are observed 3
Safety Monitoring
Essential monitoring parameters:
- Blood pressure and heart rate should be monitored at each dose adjustment, as guanfacine causes modest reductions in both 3, 4
- Most common adverse effects include somnolence (38.6%), headache (20.5%), fatigue (15.2%), and dry mouth 5
- Warnings exist for hypotension, bradycardia, cardiac conduction abnormalities, and sedation 3, 4
Discontinuation Protocol
Avoid abrupt withdrawal:
- Rebound hypertension can occur 2-4 days after discontinuation, though the frequency is low 2
- Blood pressure typically returns to pretreatment levels slowly (within 2-4 days) without ill effects in most cases 2
- Withdrawal symptoms are generally mild and occur less frequently than with clonidine 6, 7
- Gradual tapering is recommended rather than abrupt cessation 2, 7
Comparison to Pediatric Dosing
For context, the pediatric ADHD dosing follows the same weight-based approach (0.05-0.12 mg/kg/day), with the same 1 mg weekly titration schedule and 1-7 mg/day maximum range 1. The adult off-label dosing essentially mirrors this pediatric FDA-approved regimen.