For an 11-year-old patient with Attention Deficit Hyperactivity Disorder (ADHD) and hypomania, currently being treated with Selective Serotonin Reuptake Inhibitors (SSRIs), which medication is more mild for managing impulsiveness, Tenex (guanfacine) or Intuniv (extended-release guanfacine)?

Intuniv (Extended-Release Guanfacine) is the More Appropriate Choice

For an 11-year-old with ADHD and SSRI-induced hypomania, Intuniv (guanfacine extended-release) is the preferred option over Tenex (immediate-release guanfacine) because it provides more stable 24-hour coverage with fewer adverse effects, better tolerability, and superior efficacy for impulsivity control. 1, 2, 3

Critical Context: Tenex and Intuniv Are the Same Medication

• Tenex and Intuniv both contain guanfacine—the only difference is the formulation (immediate-release vs. extended-release). 2, 3
• Immediate-release guanfacine (Tenex) requires multiple daily doses and is not substitutable on a mg-for-mg basis with extended-release formulation due to different pharmacokinetics. 2
• The extended-release formulation (Intuniv) is specifically FDA-approved for ADHD in children aged 6-17 years, while Tenex is FDA-approved only for hypertension. 2, 4

Why Intuniv is Superior for This Patient

More Stable Drug Levels = Better Tolerability

• Intuniv provides once-daily dosing with around-the-clock symptom control, avoiding the peaks and troughs associated with immediate-release formulations that can worsen side effects like sedation. 1, 3
• The extended-release formulation is associated with fewer adverse effects compared to immediate-release guanfacine, making it objectively "more mild" in clinical practice. 3

Stronger Evidence Base for ADHD and Impulsivity

• The American Academy of Pediatrics explicitly recommends extended-release guanfacine for elementary school-aged children (6-11 years) with ADHD, with quality of evidence A/strong recommendation. 5
• Guanfacine extended-release demonstrates effect sizes of approximately 0.7 for ADHD symptoms, with documented improvements in impulsivity, functional impairment, and quality of life. 1, 3
• In children with ADHD and oppositional symptoms (which often include impulsivity), guanfacine extended-release showed significant reductions in oppositional behaviors with an effect size of 0.59 for oppositional symptoms and 0.92 for ADHD symptoms. 6

Safer in Context of SSRI-Induced Hypomania

• Guanfacine works through alpha-2A adrenergic receptor agonism, a completely different mechanism than SSRIs or stimulants, avoiding further mood destabilization. 1, 4
• The medication does not affect dopamine or serotonin systems, making it less likely to exacerbate mood symptoms compared to stimulants, which would be contraindicated in active hypomania. 1
• Evening administration of Intuniv can help with sleep disturbances that often accompany hypomania, while providing continuous daytime coverage for impulsivity. 1

Practical Implementation Algorithm

Starting Dose and Titration

• Begin with 1 mg once daily in the evening to minimize daytime somnolence, which is the most common adverse effect. 1, 2
• Titrate by 1 mg weekly based on response and tolerability, targeting a weight-adjusted dose of 0.05-0.12 mg/kg/day (maximum 7 mg/day). 1
• For an average 11-year-old weighing 35-40 kg, the target therapeutic range would be approximately 2-4 mg daily. 1, 7

Timeline Expectations

• Counsel the family that therapeutic effects require 2-4 weeks to become apparent, unlike stimulants which work immediately. 1
• This delayed onset is critical to prevent premature discontinuation due to perceived lack of efficacy. 1

Monitoring Requirements

• Obtain baseline blood pressure and heart rate before initiating treatment. 1, 2
• Monitor vital signs at each dose adjustment, as guanfacine causes modest decreases in blood pressure (1-4 mmHg) and heart rate (1-2 bpm). 1, 4
• Screen for personal or family history of cardiac conditions including Wolf-Parkinson-White syndrome, sudden death, or long QT syndrome. 1

Common Adverse Effects and Management

• Somnolence (50.7%) and sedation (13.2%) are most common during dose titration but typically resolve over time. 6
• Most sedation-related adverse events (63.5%) resolve prior to completing the titration period. 6
• Evening dosing minimizes daytime sedation that could interfere with school performance. 1
• Other common effects include headache (22%), fatigue (11%), and upper abdominal pain (12%), most of which are mild to moderate. 6

Critical Safety Warning

• Never abruptly discontinue guanfacine—it must be tapered by 1 mg every 3-7 days to avoid rebound hypertension. 1
• This applies to both Tenex and Intuniv formulations. 1

Why Not Tenex (Immediate-Release)?

• Immediate-release guanfacine requires multiple daily doses, reducing adherence in an 11-year-old. 2
• The immediate-release formulation has more pronounced peaks and troughs, leading to greater sedation during peak levels and potential symptom breakthrough during troughs. 3
• Lack of FDA approval for ADHD means using Tenex would be off-label, whereas Intuniv has specific approval and extensive safety data in this age group. 2, 4

Position in Treatment Algorithm

• The American Academy of Pediatrics ranks non-stimulant medications with stimulants having the strongest evidence, followed by atomoxetine, then extended-release guanfacine, then extended-release clonidine. 5
• However, in this specific case with SSRI-induced hypomania, stimulants are contraindicated due to risk of worsening mood instability. 1
• Guanfacine becomes the preferred first-line option given the mood instability, making it more appropriate than atomoxetine in this clinical context. 1