Guanfacine Uses, Dosage, Side Effects & Warnings | DrugsAtlas

Authoritative Clinical Reference

DRUG NAME: Guanfacine

Therapeutic Class: Centrally Acting Alpha-2 Agonist
Subclass: Centrally Acting, Selective Alpha-2A Agonist
Speciality: Psychiatry

Schedule (India): H
Route(s): Oral

Formulations Available in India:

Extended-release (XR/ER) tablets: 1 mg, 2 mg
Extended-release (XR/ER) tablets: 3 mg, 4 mg (available from select manufacturers; confirm regional availability)

⚠️ Immediate-release (IR) tablets are NOT readily available in the current Indian market.
⚠️ Availability of guanfacine in India is limited. It is marketed by few manufacturers and may not be stocked in all regions. Confirm availability before prescribing.

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India)

1. Attention Deficit Hyperactivity Disorder (ADHD) — Ages 6–17 Years

The primary approved indication for guanfacine in India is paediatric ADHD (ages 6–17 years) using the extended-release formulation. Detailed weight-based dosing is provided in the Paediatric Dosing section below.

May be used as monotherapy or as adjunctive therapy to stimulants (e.g., methylphenidate) when stimulant response is suboptimal or stimulants are not tolerated
Initiate only under specialist supervision (child psychiatrist / paediatric neurologist / developmental paediatrician)
Extended-release formulation ONLY — do not crush, chew, or split XR tablets

Secondary Indications — Adults Only (Off-label)


Indication	Dose (XR formulation)	Duration	Notes
Hypertension — Adults — OFF-LABEL in current Indian practice	Starting dose: 1 mg XR once daily at bedtime. Titration: increase by 1 mg every 1–2 weeks. Usual maintenance: 2–3 mg once daily. Maximum: 4 mg/day.	Long-term	Not recommended in Indian hypertension guidelines (API, ICMR). Not first- or second-line. May be considered only in refractory cases intolerant to standard agents, under specialist supervision. Originally developed as IR antihypertensive — IR formulation is NOT available in India. Evidence: Historical FDA approval for HTN (IR); not endorsed by any current Indian guideline.
Adult ADHD — OFF-LABEL	Starting dose: 1 mg XR once daily. Titration: increase by 1 mg weekly. Usual maintenance: 1–4 mg once daily. Maximum: 4 mg/day.	Long-term	Specialist only (psychiatrist). May be used as monotherapy or adjunct to stimulants. Evidence: International RCTs in adult ADHD; limited but growing Indian specialist practice.
Generalised anxiety disorder — OFF-LABEL	Starting dose: 1 mg XR once daily. Titration: increase by 1 mg weekly. Usual maintenance: 1–3 mg once daily. Maximum: 4 mg/day.	Variable; specialist-determined	Specialist only (psychiatrist). Do NOT split dose — XR is once-daily formulation. Evidence: Small-scale international RCTs and observational studies; limited Indian data.

PAEDIATRIC DOSING (Specialist Only)

⚠️ Minimum age: 6 years. Not recommended below 6 years of age except under direct specialist supervision at a tertiary care centre with specific justification.

⚠️ Extended-release formulation ONLY. Do not crush, chew, or split XR tablets.

Primary Indications (Approved / Standard in India)

1. ADHD — Ages 6–17 Years (Extended-Release Formulation)

Weight-based dosing table:


Weight Category	Starting Dose	Titration	Target Maintenance Range	Maximum Dose
<25 kg	1 mg XR once daily	Increase by 1 mg/week (not faster)	0.05–0.08 mg/kg/day	2 mg/day
25–41.4 kg	1 mg XR once daily	Increase by 1 mg/week (not faster)	0.05–0.08 mg/kg/day	3 mg/day
≥41.5 kg	1 mg XR once daily	Increase by 1 mg/week (not faster)	0.05–0.12 mg/kg/day	4 mg/day

Key clinical notes:

Administer at the same time each day, preferably in the morning or evening — timing should be consistent
Do NOT administer with a high-fat meal — increases Cmax by ~75% and AUC by ~40%, raising risk of hypotension and sedation. Administer consistently either with or without food (avoid high-fat meals)
Daytime sedation is common initially — may improve over 2–3 weeks; if given at bedtime, assess next-day drowsiness
If a dose is missed: do not double the next dose; resume normal schedule. If ≥2 consecutive doses missed, consider re-titration from a lower dose
Discontinuation: Taper gradually — reduce by no more than 1 mg every 3–7 days. Abrupt withdrawal can cause rebound hypertension, tachycardia, and agitation
Can be used as monotherapy OR as adjunct to methylphenidate/stimulant therapy
Reassess clinical response at 4–8 weeks after target dose achieved
If no meaningful benefit at maximum tolerated dose, taper and discontinue

Safety monitoring during treatment:

Blood pressure and heart rate: at baseline, after each dose change, and periodically (every 3 months)
ECG: if cardiac history or symptoms; not required routinely for all patients
Height, weight, and BMI: every 6 months (monitor growth trajectory)
Sedation/somnolence assessment: at each visit during titration
Behavioural rating scales (e.g., ADHD-RS, CGI-S): at baseline and periodically to assess response

Secondary Indications — Paediatric Doses (Off-label)


Indication	Dose (XR)	Duration	Notes
Tic disorders / Tourette syndrome — OFF-LABEL	Starting dose: 1 mg XR once daily. Titration: increase by 1 mg weekly. Usual maintenance: 1–3 mg once daily. Maximum: 4 mg/day (weight-dependent, as per ADHD table).	Long-term; reassess periodically	Specialist only (paediatric neurologist / child psychiatrist). Evidence: International RCTs demonstrating tic reduction; Indian specialist experience at tertiary centres (AIIMS, NIMHANS). May be combined with ADHD management in children with comorbid tics and ADHD.
Oppositional/disruptive behaviour in ADHD — OFF-LABEL	As per ADHD dosing above	As per ADHD	Specialist only. Often considered when stimulant alone inadequately addresses oppositional symptoms. Evidence: Sub-group analyses of ADHD RCTs; Indian specialist practice.

RENAL ADJUSTMENT


Renal Function	Recommendation
Mild-moderate impairment (eGFR 30–89)	No significant dose adjustment required; guanfacine is primarily hepatically metabolised
Severe impairment (eGFR <30)	Use with caution; initiate at lower end of dosing range (1 mg); titrate slowly; active metabolites may accumulate
Haemodialysis	No established data; dialysability unknown. Use alternate agents if possible; if used, monitor closely

HEPATIC ADJUSTMENT


Severity	Recommendation
Mild impairment	No specific dose adjustment; monitor for increased sedation and hypotension (bioavailability may increase due to reduced first-pass metabolism)
Moderate impairment	Initiate cautiously at 1 mg; slower titration (increase at ≥2-week intervals); monitor sedation, BP, HR, and LFTs
Severe impairment	Avoid if possible. Guanfacine undergoes extensive hepatic metabolism via CYP3A4; unpredictable drug levels and increased adverse effect risk. If no alternative exists, use only under specialist supervision with close monitoring.

CONTRAINDICATIONS

Known hypersensitivity to guanfacine or any excipients
Current severe symptomatic bradycardia (HR <50 bpm) or symptomatic hypotension (SBP <90 mmHg)
Concurrent use with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, nefazodone) in patients already on high-dose guanfacine — risk of severe hypotension and over-sedation (dose reduction required if combination is unavoidable — see Major Drug Interactions)

CAUTIONS

Cardiovascular disease: Risk of dose-dependent hypotension, bradycardia, and syncope — assess cardiac status before initiation
History of bradycardia or hypotension: Not an absolute contraindication but requires close monitoring; start at lowest dose
QTc prolongation: Dose-dependent QTc prolongation has been observed; avoid in patients with known long QT syndrome, family history of sudden cardiac death, or concomitant QT-prolonging drugs. Obtain ECG if risk factors present
Sedation/somnolence: Prominent, especially during initiation and titration — may impair school performance in children, driving ability in adolescents/adults. Counsel accordingly
Abrupt withdrawal: Can precipitate rebound hypertension, tachycardia, anxiety, and agitation — always taper gradually (reduce by ≤1 mg every 3–7 days)
Concurrent sedative use: Enhanced CNS depression with benzodiazepines, opioids, alcohol, antihistamines, antipsychotics — use with caution
Hepatic impairment: Increased bioavailability and unpredictable drug levels (see Hepatic Adjustment)
Depression / suicidal ideation: Monitor for emergence or worsening of depressive symptoms and suicidal thinking, especially in adolescents
Dehydration / volume depletion: Increased risk of hypotension
Contact lens wearers: May reduce lacrimation
Concomitant antihypertensives or vasodilators: Additive hypotensive effect

PREGNANCY


Parameter	Detail
Overall safety statement	Limited human data; animal studies show adverse developmental effects at high doses. Use only if potential benefit clearly justifies risk to fetus.
Risk category	Not formally classified in India; comparable to US FDA former Category B (animal data) / insufficient human data
Preferred alternatives	For ADHD in pregnancy: prioritise behavioural/psychoeducational interventions first. If pharmacotherapy essential: methylphenidate may be considered under specialist supervision (more safety data available). For hypertension: labetalol, methyldopa, nifedipine are standard Indian choices.
When to use	Only when no suitable alternative exists; specialist decision (psychiatrist + obstetrician)
Maternal monitoring	Blood pressure, heart rate, sedation
Fetal monitoring	Fetal growth scans; fetal heart rate monitoring
Peripartum	If used near delivery, monitor neonate for hypotension, bradycardia, and sedation

LACTATION


Parameter	Detail
Breastfeeding compatibility	Insufficient data — excretion into human breast milk is not well studied
Drug levels in milk	Not established; expected to be present given high lipophilicity
Preferred alternatives	Atomoxetine (for ADHD — more data available, though still limited); for maternal hypertension, labetalol or nifedipine preferred
Infant monitoring	If used: observe for sedation, poor feeding, excessive drowsiness, bradycardia, and inadequate weight gain
Recommendation	Avoid during breastfeeding unless no suitable alternative exists; specialist input mandatory

ELDERLY

Not commonly used in elderly patients in India
If prescribed (e.g., for off-label hypertension):
- Starting dose: 1 mg XR once daily (0.5 mg is NOT possible — XR tablets cannot be split)
- Slower titration: increase at intervals of no less than 2 weeks
- Extra risks: Exaggerated hypotensive response, orthostatic hypotension, falls, syncope, bradycardia, excessive sedation, cognitive effects (confusion, drowsiness)
- Concomitant medications: Review carefully — elderly often on multiple antihypertensives, sedatives, or QT-prolonging agents
- Monitoring: Orthostatic BP, heart rate, cognitive function, fall risk assessment at each visit

MAJOR DRUG INTERACTIONS


Interacting Drug/Class	Mechanism / Risk	Action
Strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir, clarithromycin, nefazodone)	Guanfacine is a CYP3A4 substrate; strong inhibitors markedly increase plasma levels → risk of severe hypotension, bradycardia, over-sedation	Reduce guanfacine dose by 50% when co-administered; if inhibitor is discontinued, increase guanfacine dose back to original over 1–2 weeks
Strong CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, phenobarbital, St John's Wort)	Significantly reduce guanfacine plasma levels → risk of loss of efficacy and potential withdrawal symptoms	Consider doubling guanfacine dose over 1–2 weeks if inducer is added; when inducer is stopped, reduce guanfacine over 1–2 weeks to avoid toxicity. Rifampicin is especially potent — may reduce guanfacine exposure by >70%.
CNS depressants (benzodiazepines, opioids, barbiturates, alcohol)	Additive CNS depression → excessive sedation, respiratory depression	Avoid or minimise concurrent use; if unavoidable, monitor sedation closely
Valproate (valproic acid / divalproex)	May increase guanfacine plasma levels (mechanism not fully elucidated; possibly CYP inhibition) → increased sedation and hypotension risk	Monitor closely for sedation and hypotension; consider guanfacine dose reduction

MODERATE DRUG INTERACTIONS


Interacting Drug/Class	Mechanism / Risk	Action
Antihypertensives (beta-blockers, ACEIs, ARBs, CCBs, diuretics)	Additive hypotension and/or bradycardia	Monitor BP and HR; dose adjustment of either agent may be needed
Methylphenidate (commonly co-prescribed for ADHD)	Pharmacodynamic interaction: guanfacine may lower BP while methylphenidate may raise BP; net effect variable	Monitor BP and HR closely during co-titration; generally safe combination with appropriate monitoring
Tricyclic antidepressants (amitriptyline, imipramine)	May blunt guanfacine's antihypertensive effect (central noradrenergic mechanism); additive sedation	Monitor BP and sedation
Moderate CYP3A4 inhibitors (erythromycin, fluconazole, diltiazem, verapamil, grapefruit juice)	Moderate increase in guanfacine levels	Monitor for increased sedation and hypotension; dose adjustment may be needed
QTc-prolonging drugs (ondansetron, domperidone, fluoroquinolones, certain antipsychotics)	Guanfacine has dose-dependent QTc effect; additive risk	Avoid combination if possible; if necessary, obtain ECG and monitor
Antihistamines (hydroxyzine, diphenhydramine, chlorpheniramine)	Additive sedation and anticholinergic effects	Warn about excessive drowsiness; use cautiously

COMMON ADVERSE EFFECTS

Somnolence / sedation (most common — up to 30–40% in paediatric ADHD trials; usually diminishes over weeks)
Fatigue / tiredness
Headache
Dizziness
Hypotension (orthostatic and sustained)
Bradycardia
Abdominal pain / nausea
Dry mouth
Decreased appetite
Irritability (especially during early titration and dose changes)
Insomnia (if administered in the morning in some patients)

SERIOUS ADVERSE EFFECTS


Adverse Effect	Clinical Significance
Syncope	More common during titration or with concomitant antihypertensives; assess hydration, postural BP
Severe bradycardia (HR <50 bpm in adults; <60 bpm in children)	May require dose reduction or discontinuation; obtain ECG
Severe hypotension (SBP <90 mmHg or symptomatic)	Hold dose; reassess indication; volume resuscitation if needed
Rebound hypertension (on abrupt withdrawal)	Can be clinically significant — always taper; may require temporary antihypertensive cover
QTc prolongation	Dose-dependent; risk of arrhythmia at high doses or with concomitant QT-prolonging drugs; obtain ECG
Hepatotoxicity	Rare; isolated reports of transaminase elevation. Monitor LFTs if clinical symptoms arise.
Suicidal ideation / depression	Monitor in adolescents; reassess risk-benefit if mood symptoms emerge

MONITORING REQUIREMENTS


Timing	Parameters
Baseline (before initiation)	Blood pressure (sitting and standing), heart rate, ECG (if cardiac history or risk factors for QTc prolongation), height, weight, BMI (in children), LFTs (if hepatic concerns), behavioural rating scale (ADHD-RS / CGI-S)
During titration (each dose increase)	BP and HR (before and 1–2 hours post-dose, or at least trough before next dose); sedation assessment; sleep pattern; mood assessment (in adolescents)
After target dose achieved	BP, HR, sedation at 4-week follow-up; behavioural response assessment
Long-term (chronic use)	BP, HR every 3 months; height, weight, BMI every 6 months (in children — monitor growth trajectory); behavioural assessment every 3–6 months; LFTs annually or if symptoms; ECG if new cardiac symptoms or QT-prolonging drugs added
On discontinuation	Taper over at minimum 1 week (reduce by ≤1 mg every 3–7 days); monitor BP and HR during taper and for at least 1 week after last dose to detect rebound hypertension

BRANDS AVAILABLE IN INDIA

⚠️ Availability of guanfacine in India is limited. Few manufacturers market this product. Confirm availability before prescribing.


Brand Name	Manufacturer	Available Forms
Intuniv®	Takeda (imported; limited distribution)	Extended-release tablets
Indian generic brands	Select Indian manufacturers (emerging market)	Extended-release tablets (1 mg, 2 mg)

(Note: "Guanfadine" listed in some sources could not be verified as a genuine marketed brand in India and has been excluded. Prescribers should confirm brand availability with regional distributors.)

PRICE RANGE (INR)


Formulation	Approximate Price Range	Notes
XR tablet 1 mg	₹25–50 per tablet	Varies significantly by brand and availability
XR tablet 2 mg	₹45–80 per tablet	Limited competition; may be higher
NLEM status	NOT on NLEM 2022	Not price-controlled under NPPA
Government supply	Not available through government supply / Jan Aushadhi as of current data	Entirely private market

(Prices are indicative and may vary widely given limited manufacturers and regional distribution.)

CLINICAL PEARLS

Guanfacine vs Clonidine for ADHD in India: Guanfacine is more selective for alpha-2A receptors (prefrontal cortex) than clonidine (which acts at alpha-2A, 2B, and 2C), resulting in potentially better cognitive effects and less overall sedation at steady state. However, clonidine is far more widely available and cheaper in India — consider availability and cost when choosing.
Never stop abruptly — rebound hypertension can occur even in normotensive children on guanfacine for ADHD. Always taper by ≤1 mg every 3–7 days.
High-fat food warning: A high-fat meal increases XR exposure by ~40–75%, raising the risk of hypotension and excessive sedation. Counsel families to administer the dose consistently (always with food OR always without, but avoid high-fat meals at dosing time).
XR tablets must NOT be crushed, chewed, or split — this destroys the extended-release mechanism, causing dose-dumping with potential severe hypotension and sedation.
Bedtime dosing vs morning dosing: Traditionally given at bedtime to mitigate daytime sedation. However, some patients may benefit from morning dosing if insomnia is a problem. Be flexible but consistent.
Atomoxetine remains the more established non-stimulant option in India for ADHD, with wider availability and more prescriber familiarity. Reserve guanfacine for cases where stimulants and atomoxetine are insufficient, not tolerated, or contraindicated — or when comorbid tics, anxiety, or oppositional behaviour favour an alpha-2 agonist approach.

VERSION

RxIndia v0.5 — 18 Feb 2026

REFERENCES

CDSCO prescribing information (where available for guanfacine)
National Formulary of India (NFI)
IAP Consensus Guidelines on ADHD Management
API Textbook of Medicine (for centrally acting antihypertensives — reference only)
AIIMS Drug Formulary
Indian paediatric psychiatry expert consensus (ADHD pharmacotherapy)
Goodman & Gilman's The Pharmacological Basis of Therapeutics (pharmacology reference — alpha-2 agonist mechanism)
KD Tripathi — Essentials of Medical Pharmacology (centrally acting sympatholytics)
International RCTs: Guanfacine XR in paediatric ADHD (Biederman et al., Sallee et al.); used for off-label evidence basis only
International RCTs: Guanfacine in tic disorders (Murphy et al., Cummings et al.); used for off-label evidence basis only

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Clinical Responsibility

This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.

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