Guanfacine
Guanfacine extended-release is a non-stimulant medication indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children and adolescents aged 6-17 years. It may be used as monotherapy or as adjunctive therapy with stimulant medications for comprehensive ADHD management.
Clinical Overview
Primary Clinical Applications
Guanfacine XR is particularly valuable for patients who cannot tolerate stimulant medications or require additional symptom control when used with stimulants. It is effective for hyperactivity, impulsivity, and inattention symptoms, with potential benefits for emotional regulation and aggression.
Mechanism and Clinical Benefits
As an alpha-2A adrenergic receptor agonist, guanfacine XR works in the prefrontal cortex to improve working memory and reduce distractibility. Unlike stimulants, it does not affect dopamine directly but modulates norepinephrine signaling to enhance executive function and attention.
Administration and Monitoring
The extended-release formulation allows for once-daily dosing and provides 24-hour symptom control. Blood pressure and heart rate monitoring is essential, particularly during dose titration, as the medication can cause hypotension and bradycardia.
Key Clinical Points
Paediatric indication only
Approved for ADHD in children and adolescents aged 6 to 17. It is not approved for adult ADHD, which is a common source of off-label prescribing.
Blood pressure and heart rate monitoring
Alpha-2A agonism produces dose-related hypotension and bradycardia, with syncope most likely during initiation and dose increases. Measurement at each titration step is required rather than optional.
Rebound hypertension on abrupt cessation
Stopping suddenly can produce rebound hypertension. A gradual taper is needed, which patients and families often do not anticipate for what they regard as a behavioural medication.
Works alongside stimulants
Licensed as monotherapy or as adjunct to stimulants, and may add benefit for emotional regulation and aggression beyond core ADHD symptoms.
Tablets must be swallowed whole
Crushing or chewing destroys the extended-release mechanism. CYP3A4 inducers may require doubling the dose, while inhibitors call for reduction.
Prescribing Information
Dosing & Administration
ADHD – Children and Adolescents (6-17 years):
- Initial: 1 mg once daily
- Titration: Increase by 1 mg weekly as tolerated
- Target range: 1-4 mg once daily
- Maximum: 4 mg once daily
- Weight-based dosing: 0.05-0.12 mg/kg/day
Administration:
- Take once daily in morning or evening
- May take with or without food
- Swallow tablets whole, do not crush or chew
- Consistent timing each day
Indications
- Treatment of ADHD in children and adolescents (6-17 years)
- May be used as monotherapy or adjunctive with stimulants
Contraindications
- Hypersensitivity to guanfacine or any component
- No absolute contraindications, but caution in cardiovascular disease
Warnings & Precautions
- Hypotension and bradycardia: Monitor blood pressure and heart rate
- Sedation and somnolence: May impair ability to operate machinery
- Syncope: Risk particularly during dose initiation and increases
- Rebound hypertension: Taper gradually when discontinuing
- Cardiac conduction abnormalities: Use caution in patients with heart block
Drug Interactions
- CYP3A4 inducers: May require dose increase up to double
- CYP3A4 inhibitors: Consider dose reduction
- Antihypertensives: Enhanced hypotensive effects
- CNS depressants: Increased sedation risk
Adverse Reactions
Common (≥5%):
- Somnolence, headache, fatigue, upper abdominal pain
- Irritability, hypotension, nausea, lethargy
Cardiovascular:
- Decreased blood pressure and heart rate, syncope
Special Populations
- Renal Impairment: Consider dose reduction in severe impairment
- Hepatic Impairment: Consider dose reduction
- Adults: Not approved for adult ADHD
- Cardiovascular Disease: Monitor closely, may worsen existing conditions
Frequently Asked Questions
What is Guanfacine XR used for?
Guanfacine extended-release is a non-stimulant medication indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children and adolescents aged 6-17 years. It may be used as monotherapy or as adjunctive therapy with stimulant medications for comprehensive ADHD management.
What class of drug is Guanfacine XR?
Guanfacine XR is classified as: Alpha-2 Adrenergic Agonist.
Paediatric indication only?
Approved for ADHD in children and adolescents aged 6 to 17. It is not approved for adult ADHD, which is a common source of off-label prescribing.
Blood pressure and heart rate monitoring?
Alpha-2A agonism produces dose-related hypotension and bradycardia, with syncope most likely during initiation and dose increases. Measurement at each titration step is required rather than optional.
Rebound hypertension on abrupt cessation?
Stopping suddenly can produce rebound hypertension. A gradual taper is needed, which patients and families often do not anticipate for what they regard as a behavioural medication.
Works alongside stimulants?
Licensed as monotherapy or as adjunct to stimulants, and may add benefit for emotional regulation and aggression beyond core ADHD symptoms.
Source: FDA prescribing information (DailyMed)