Intuniv

(guanfacine ER)

Intuniv (guanfacine); not controlled

Summary

Intuniv is extended-release guanfacine, a central alpha-2A adrenergic agonist approved for ADHD in patients 6 to 17 years, as monotherapy or added to a stimulant. It is a once-daily tablet dosed by body weight rather than by age, and its selectivity for the alpha-2A subtype makes it less sedating than clonidine. It is the alpha-2 agonist to reach for when a stimulant is insufficient or poorly tolerated and daytime sedation is the limiting concern. Not controlled; brand and generic.

Forms & Strengths

• Tablets, extended release: 1 mg, 2 mg, 3 mg, 4 mg; unscored
• These are tablets, not capsules. No guanfacine capsule exists in any form
• Separate label: immediate-release guanfacine tablets 1 mg and 2 mg (formerly Tenex), not interchangeable mg-for-mg

Dosing

• Age: 6-17 y/o; not established below 6 years
• Onset: sedation same day; ADHD benefit over weeks, trial endpoints at 5 to 8 weeks
• Duration: once daily, morning or evening, same time each day; half-life about 18 hours
• Release Profile: extended release from a matrix tablet; Cmax about 60% lower and AUC about 43% lower than immediate-release guanfacine, Tmax about 3 hours later, relative bioavailability 58%
• Initial Dose: 1 mg once daily
• Titration: no more than 1 mg every 7 days
• Max Dose: target 0.05 to 0.12 mg/kg/day, total 1 mg to 7 mg/day. Two age ceilings sit above the weight bands and both apply:
  • 6-12 y/o: do not exceed 4 mg/day
  • 13-17 y/o: do not exceed 7 mg/day
  • As adjunct to a stimulant: do not exceed 4 mg/day at any age
  • Under 25 kg: no weight band; dose from 0.05 to 0.12 mg/kg/day, starting at 1 mg
  • 25 to 33.9 kg: 2 to 3 mg/day
  • 34 to 41.4 kg: 2 to 4 mg/day
  • 41.5 to 49.4 kg: 3 to 5 mg/day
  • 49.5 to 58.4 kg: 3 to 6 mg/day
  • 58.5 to 91 kg: 4 to 7 mg/day
  • Over 91 kg: 5 to 7 mg/day
• Considerations: Swallow whole and do not give with a high-fat meal, which raises Cmax about 75%. Halve the dose with strong or moderate CYP3A4 inhibitors, and re-check the weight band as the child grows.

Pharmacology

• Mechanism: Central alpha-2 adrenergic agonist; reduces sympathetic outflow from the locus coeruleus and enhances prefrontal noradrenergic signalling. Alpha-2A selective, 15 to 20 fold. Mechanism in ADHD unknown.
• Delivery / Release: Matrix tablet; a high-fat breakfast raises Cmax about 75% and AUC about 40%.
• Metabolism: Primarily CYP3A4; neither inhibits nor induces major P450s. About 70% protein bound. Inhibits MATE1 and OCT1, which may raise OCT1 substrate exposure.
• Pediatric exposure: higher in 6-12 year olds than in adolescents at the same dose (4 mg: Cmax 10 vs 7 ng/mL, AUC 162 vs 116 ng.h/mL). Plasma level falls as weight rises, hence weight banding.
• Cardiac: a thorough QT study at 2 to 4 times maximum Intuniv concentrations showed no clinical QTc prolongation.
• Class Positioning: Less sedating than non-selective clonidine; once daily against twice-daily Kapvay, weight-banded, with a CYP3A4 profile clonidine lacks. Alpha-2 effect size about 0.7 against 1.0 for stimulants. (AAP 2019)

Indications

• ADHD, as monotherapy (ICD-10: F90.0, F90.1, F90.2, F90.8, F90.9): patients 6-17 y/o
• ADHD, as adjunctive therapy to stimulants (ICD-10: F90.0, F90.1, F90.2, F90.8, F90.9): patients 6-17 y/o

Off-Label Uses

• Tic disorders and Tourette syndrome (ICD-10: F95.1, F95.2): a positive double-blind trial for tic severity, the better tic evidence of the two alpha-2 agonists. (AACAP 2013)
• Oppositional defiant disorder, irritability and aggression (ICD-10: F91.3): no eligible controlled pediatric evidence identified; insufficient
• Irritability in autism spectrum disorder (ICD-10: F84.0): limited data
• Where the evidence does not support use:
  • Anxiety disorders (ICD-10: F41.x): insufficient; no graded pediatric evidence identified
  • Children under 6 (ICD-10: F90.x): insufficient (AHRQ 2018), and exposure rises as weight falls

Contraindications & Warnings

• Warning, rebound hypertension: abrupt discontinuation has caused persistent rebound hypertension above baseline, with hypertensive encephalopathy reported
• Contraindicated: hypersensitivity to Intuniv, its excipients, or other guanfacine products; rash and pruritus reported
• Use with caution:
  • Hypotension, heart block, bradycardia, cardiovascular or cerebrovascular disease; titrate slowly
  • Syncope, orthostatic hypotension, or a tendency to dehydration; avoid overheating
  • Conduction abnormality, concurrent sympatholytics or CNS depressants; risk of AV block and additive sedation
  • Significant renal or hepatic impairment; reduce the dose
  • Any child prone to vomiting illness; missed doses are a labeled rebound risk
• Screen before starting:
  • Heart rate and blood pressure, supine and standing; the label makes this mandatory
  • Accurate weight, since the dose ladder is banded by it; renal and hepatic function
  • Medication list, screened for CYP3A4 inhibitors and inducers, sedating and sympatholytic agents, and any syncope or conduction history

Drug Interactions

• Strong and moderate CYP3A4 inhibitors (ketoconazole, fluconazole, itraconazole, clarithromycin, erythromycin, grapefruit juice): exposure rises. Halve the dose; restore it when the inhibitor stops
• Strong and moderate CYP3A4 inducers (rifampin, efavirenz, carbamazepine): exposure falls. Consider up to double the dose over 1 to 2 weeks, and reverse when the inducer stops
• CNS depressants and alcohol (benzodiazepines, antihistamines, opioids): additive sedation; advise avoiding alcohol
• Antihypertensives and rate-lowering drugs: additive hypotension and syncope; check orthostatic vitals after any dose change
• Sympatholytics (beta-blockers, calcium channel blockers, digitalis): may worsen sinus node dysfunction and AV block; titrate slowly
• Stimulants: the labeled combination, but featured in the rebound hypertension cases; taper the guanfacine even when the stimulant continues

Administration

• Once daily, morning or evening, at about the same time each day
• Swallow whole. Do not crush, chew or break; the tablet is unscored, so 1 mg is the smallest deliverable dose
• Do not give with a high-fat meal. A prohibition, not a consistency instruction
• Missed doses: after two or more in a row, consider re-titrating rather than resuming maintenance
• Switching from immediate-release guanfacine: stop it and titrate from 1 mg; relative bioavailability is 58%, so never convert mg-for-mg
• Re-check the weight band at every visit in a growing child
• No liquid guanfacine exists; Onyda XR is the only liquid alpha-2 agonist, and it is clonidine
• Do not stop abruptly; see Discontinuation & Taper

Side Effects

• Common (fixed-dose monotherapy trials, all doses and the 4 mg column against placebo):
  • Somnolence 38%, 51% at 4 mg, vs 11% placebo; fatigue 14 / 15 vs 3%
  • Hypotension 7 / 8 vs 3%; dizziness 6 / 10 vs 4%; dry mouth 4 / 7 vs 1%; lethargy 6 vs 3%; nausea 6 vs 2%
  • Stopped for adverse effects: 3% at 1 mg, 7% at 2 mg, 10% at 3 mg, 18% at 4 mg, vs 3% placebo
• Serious:
  • Persistent rebound hypertension on abrupt discontinuation, with hypertensive encephalopathy reported; taper
  • Dose-dependent hypotension, bradycardia and syncope; hold or reduce, and any syncope stops titration
  • Conduction abnormality including first-degree AV block; obtain an ECG and stop
  • Convulsion; discontinue and evaluate
  • Rash, pruritus, dermatitis and exfoliative dermatitis; discontinue
  • Hallucinations and confusion; discontinue and reassess
  • Raised ALT; check liver enzymes if hepatic injury is suspected

Monitoring & Labs

• Heart rate and blood pressure, supine and standing: baseline, 1 to 2 weeks after each 1 mg increment, then every 3 months; hold titration for bradycardia by age or any syncope
• Blood pressure and pulse during any dose reduction: at each step down and after the last dose
• Sedation: ask about school-day sleepiness at each titration visit and every visit for 3 months
• Weight: at every visit, to keep the dose in the right band
• ADHD response: rated scale at 5 to 8 weeks, matching the trial endpoints
• CYP3A4 co-medication: review at every visit and refill; starting or stopping one requires a dose change
• ECG: not routine; baseline if conduction disease, syncope history or sympatholytics, and promptly for new syncope
• Renal and hepatic function: baseline and annually
• Laboratory: none routine; check ALT if hepatic injury is suspected

Discontinuation & Taper

• Never stop abruptly. Reduce by no more than 1 mg every 3 to 7 days; from 7 mg/day that is 3 to 6 weeks
• Abrupt cessation has caused persistent rebound hypertension with raised heart rate, and hypertensive encephalopathy has been reported
• Cases involved higher doses and concomitant stimulants; taper even when the stimulant continues
• Monitor blood pressure and pulse at every taper step and after the final dose
• A vomiting illness is de facto abrupt discontinuation; families should call, not let doses lapse
• After two or more consecutive missed doses, consider re-titrating
• Drug holidays are not appropriate for this class; weekend and summer breaks are a rebound hypertension risk here

Pregnancy & Lactation

• Pregnancy: no drug-associated risk identified, but pregnancy use has been infrequent. No fetal harm in rabbits and rats at 3 to 4 times the maximum human dose; reduced fetal survival at 13.5 times.
• Lactation: no human data; guanfacine has not been measured in human milk. Present in rat milk at blood-comparable levels. Monitor an exposed infant for sedation, lethargy and poor feeding. (LactMed 2024)
• Lactation, milk supply: no published information; guanfacine lowers basal prolactin in men and non-nursing women. Other agents may be preferred while nursing a newborn. (LactMed 2024)
• Exposure Registry: National Pregnancy Registry for ADHD Medications, 1-866-961-2388

Counseling Points

• Counsel the family on:

  • Sleepiness early and dose related, half the children on 4 mg, while the ADHD benefit takes 5 to 8 weeks
  • Not taking it with a high-fat breakfast, and swallowing the unscored tablet whole
  • The dose being set by weight, so it is revisited as the child grows
  • Never stopping on their own: stopping suddenly can push blood pressure above where it started
  • Telling other prescribers before an antifungal, clarithromycin, or a seizure medicine
  • Calling if a stomach bug stops the medicine going down, or after two days of missed doses

• Advise them to call for:

  • Fainting, dizziness on standing that does not settle, or any seizure
  • A pulse that feels very slow or irregular, or heavy daytime sleepiness
  • Severe headache with blurred vision, especially after missed doses
  • A widespread rash, peeling skin, facial swelling, or new confusion or hallucinations
  • Any vomiting illness that stops the medicine going down

References

1. DailyMed. Intuniv (guanfacine) extended-release tablets prescribing information. Takeda Pharmaceuticals America, Inc. 2025. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b972af81-3a37-40be-9fe1-3ddf59852528
2. LactMed. Guanfacine. Drugs and Lactation Database, National Institute of Child Health and Human Development. 2024. https://www.ncbi.nlm.nih.gov/books/NBK501522/
3. American Academy of Pediatrics. Clinical practice guideline for the diagnosis, evaluation, and treatment of attention-deficit/hyperactivity disorder in children and adolescents. Pediatrics. 2019. https://publications.aap.org/pediatrics/article/144/4/e20192528/81590/
4. AACAP. Practice parameter for the assessment and treatment of children and adolescents with tic disorders. Journal of the American Academy of Child and Adolescent Psychiatry. 2013. https://www.jaacap.org/article/S0890-8567(13)00695-3/fulltext
5. AHRQ. Attention deficit hyperactivity disorder: diagnosis and treatment in children and adolescents. Comparative Effectiveness Review No. 203. 2018. https://www.ncbi.nlm.nih.gov/books/NBK487764/
6. FDA. openFDA National Drug Code Directory, guanfacine, queried by generic name across all labelers. 2026. https://api.fda.gov/drug/ndc.json?search=generic_name:%22guanfacine%22&limit=1000