Adult Dosing of Intuniv (Guanfacine) for ADHD Treatment
For adults with ADHD, guanfacine (Intuniv) should be initiated at 1 mg/day and titrated up to an effective dose of 1-3 mg/day, with a maximum daily dose of 4 mg.
Dosing Recommendations
While the evidence specifically for adult dosing of guanfacine for ADHD is limited, research suggests the following approach:
- Initial dose: Start with 1 mg once daily
- Titration: Increase by 1 mg every 4-7 days as needed and tolerated
- Target dose range: 1-3 mg/day
- Maximum dose: 4 mg/day
This dosing recommendation is supported by research showing that guanfacine extended-release (ER) has been studied at doses up to 4 mg/day in young adults 1. The study demonstrated that doses up to 4 mg/day were generally well-tolerated.
Administration Considerations
- Administer once daily in the morning
- Take consistently with or without food
- Extended-release formulation (Intuniv) is preferred over immediate-release for ADHD treatment due to once-daily dosing and potentially fewer side effects
Monitoring and Precautions
- Blood pressure and heart rate: Monitor regularly, especially during dose titration, as guanfacine can cause hypotension and bradycardia
- Sedation: Be aware that sedation/somnolence is common, especially during the first 2 weeks of treatment
- ECG: Consider baseline ECG if cardiac risk factors are present
Discontinuation
When discontinuing guanfacine, gradual tapering is generally recommended, although research suggests that abrupt discontinuation may be tolerated in some patients 1. A conservative approach would be:
- Decrease dose by 1 mg every 3-7 days
- Monitor for potential rebound effects during discontinuation
Comparative Efficacy and Side Effect Profile
Guanfacine has several advantages over other alpha-2 agonists like clonidine:
- More selective for alpha-2A receptors
- Less sedation than clonidine
- More stable blood pressure effects
- Reduced risk of rebound hypertension upon discontinuation 2
Research has demonstrated that guanfacine can be effective for adult ADHD at an average dose of 1.1 mg/day 3, though this was a small preliminary study.
Common Side Effects
- Sedation/somnolence (most common)
- Dry mouth
- Dizziness
- Headache
- Fatigue
- Hypotension
- Bradycardia
Important Considerations
- Guanfacine is metabolized primarily through CYP3A4, so be cautious with concomitant medications that affect this enzyme
- Avoid concomitant CNS depressants when possible, as they may potentiate sedative effects
- Use with extreme caution in patients with cardiac issues
While the evidence specifically for adult ADHD treatment with guanfacine is not as robust as for pediatric populations, the available data suggests it can be an effective non-stimulant option for adults with ADHD, particularly those who cannot tolerate stimulants or have comorbid conditions like tic disorders.