What information should be included in guanfacine (Intuniv) patient education for Attention Deficit Hyperactivity Disorder (ADHD) and hypertension treatment?

Guanfacine Patient Education

Patients taking guanfacine (Intuniv) for ADHD or hypertension must understand that this medication requires careful dose titration, causes significant sedation especially early in treatment, and must never be stopped abruptly due to risk of rebound hypertension.

What Guanfacine Does

• Guanfacine is an alpha-2A adrenergic receptor agonist that works differently from stimulant ADHD medications by enhancing noradrenergic neurotransmission in the prefrontal cortex, strengthening attention, thought, and working memory 1
• Effects take 2-4 weeks to become fully apparent, unlike stimulants which work immediately, so patience during initial treatment is essential 2
• For ADHD, guanfacine provides "around-the-clock" symptom control with once-daily dosing 2
• For hypertension, it lowers blood pressure by reducing sympathetic nervous system activity 3

Dosing and Administration

• Starting dose is typically 1 mg once daily, taken at bedtime to minimize daytime sedation 1
• Dose is increased slowly by 1 mg per week based on response and tolerability, with target range of 1-7 mg/day (or 0.05-0.12 mg/kg/day in children) 1
• Evening administration is strongly preferred due to the high frequency of sedation and fatigue 1
• The medication comes in 1,2,3, and 4 mg tablets 2

Most Important Safety Warnings

Sedation and Drowsiness

• Sedation is the most common side effect, occurring in approximately 38.6% of patients 4
• Do not drive, operate machinery, or perform dangerous activities until you know how guanfacine affects you 3
• Avoid alcohol and other sedating medications (including benzodiazepines, barbiturates, phenothiazines) as they significantly increase sedation risk 3
• Sedation is dose-related and typically improves over time 3

Blood Pressure and Heart Rate Effects

• Guanfacine lowers blood pressure and heart rate in all patients, not just those with hypertension 1, 3
• Expect modest reductions in blood pressure (approximately 7-10%) and heart rate 5, 4
• Monitor for symptoms of low blood pressure: dizziness, lightheadedness, fainting, especially when standing up 3
• Blood pressure and heart rate should be monitored regularly, particularly during dose adjustments 1

Never Stop Abruptly - Critical Warning

• Guanfacine must be tapered gradually when discontinuing, never stopped suddenly 1, 2, 3
• Abrupt cessation can cause rebound hypertension (blood pressure rising significantly above pre-treatment levels), nervousness, anxiety, and increased catecholamines 3
• Taper schedule typically involves reducing by 1 mg every 3-4 days under physician supervision 5
• This withdrawal risk exists even in patients taking guanfacine for ADHD, not just hypertension 3

Common Side Effects

The most frequent side effects include 4:

• Somnolence/sedation (38.6% of patients) - usually improves with continued treatment
• Headache (20.5%) - typically mild to moderate
• Fatigue (15.2%) - often dose-related
• Dry mouth - common with alpha-2 agonists 3, 6
• Constipation - manage with adequate hydration and fiber 6

Approximately 80% of patients experience at least one side effect, compared to 66.5% with placebo, but serious adverse events are rare 4

Special Populations and Precautions

Pregnancy and Breastfeeding

• Very limited safety data exists for guanfacine in pregnancy 7
• One small study in 30 women with preeclampsia (all beyond first trimester) showed no congenital malformations, but 20% of infants had low birth weight 7
• No published studies exist on guanfacine use during breastfeeding 7
• Alternative ADHD medications are strongly preferred during pregnancy and lactation 7

Cardiac Conditions

• Use with extreme caution if you have: severe coronary insufficiency, recent heart attack, cerebrovascular disease, or cardiac conduction abnormalities 3
• Report any history of: Wolf-Parkinson-White syndrome, unexplained fainting, or family history of sudden cardiac death 7

Liver or Kidney Disease

• Patients with chronic renal or hepatic failure require careful monitoring 3
• Guanfacine is metabolized by the liver (CYP3A4) and excreted primarily by kidneys 2

Drug Interactions

Medications That Reduce Guanfacine Effectiveness

• Enzyme inducers (phenobarbital, phenytoin) significantly reduce guanfacine levels, requiring more frequent dosing and careful tapering if discontinued 3

Medications That Increase Sedation Risk

• All CNS depressants potentiate sedation: benzodiazepines, barbiturates, phenothiazines, alcohol 3
• Patients must inform all healthcare providers they are taking guanfacine before receiving sedating medications

No Significant Interactions With

• Oral anticoagulants (warfarin) 3
• Diuretics 3
• Cardiac glycosides, oral hypoglycemics, NSAIDs, oral contraceptives 3

Effectiveness for ADHD

• Guanfacine is FDA-approved and effective for ADHD with effect sizes around 0.7 compared to placebo 7
• Stimulant medications remain more effective (effect size ~1.0), making guanfacine typically a second-line option 7, 1
• Response rates are approximately 58-64% compared to 29-40% with placebo 4
• Stronger evidence exists for children than adults - more research is needed in adult populations 7, 4
• Guanfacine improves not just core ADHD symptoms but also functional impairment and quality of life 1, 2

When to Contact Your Healthcare Provider Immediately

• Severe dizziness, fainting, or feeling like you might pass out
• Chest pain, very slow heart rate, or irregular heartbeat
• Severe sedation that interferes with daily functioning
• Signs of allergic reaction: rash, itching, swelling, difficulty breathing 1
• If you accidentally miss multiple doses - do not restart at full dose without medical guidance
• Before stopping the medication for any reason - requires supervised tapering

Monitoring Requirements

• Blood pressure and heart rate checks at baseline, during dose titration, and periodically during maintenance 1
• ADHD symptom monitoring using standardized parent and teacher reports at each dose adjustment 1
• Assessment of functional impairment and quality of life to evaluate true treatment benefit 1

Important Lifestyle Considerations

• Tolerance for alcohol is diminished - avoid or minimize alcohol consumption 3
• Plan medication timing around sleep schedule - bedtime dosing minimizes daytime impairment 1
• Maintain consistent dosing schedule - steady-state levels take approximately 4 days to achieve 6
• Stay well-hydrated to help manage dry mouth and constipation 6