medicationPrescription only (US)Extended-release guanfacine (Intuniv) is FDA-approved for ADHD in children and adolescents; the currently approved maximum dose is 4 mg per day, which is lower than the highest doses reached in the cited adolescent ADHD trialUse for pediatric anxiety, as studied in the second cited trial, is not an FDA-approved indication
GuanfacineBenefits, Dosage & Interactions
Also known as: Intuniv
Intuniv is the extended-release form of guanfacine, a non-stimulant approved for ADHD in children and adolescents, alone or alongside a stimulant. It is typically taken in the evening. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
How much Guanfacine do people take?
The ADHD trial dosed once-daily extended-release guanfacine (GXR) from 1–7 mg per day, with most participants optimized between 3–6 mg; the anxiety pilot trial flexibly dosed GXR from 1–6 mg daily. Route reported: Oral, extended-release tablet, once daily, in both cited trials. Frequency reported: Once daily dosing, flexibly titrated within each trial's protocol. These are amounts documented in the cited studies and labels for Guanfacine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
See the full reported protocol and its sourcesResearched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Evidence: Strong — 2 human randomized trials and regulatory approval on file.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence
2 human randomized trials and regulatory approval on file.
Quick answer
Intuniv is the extended-release form of guanfacine, a non-stimulant approved for ADHD in children and adolescents, alone or alongside a stimulant. It is a selective alpha-2A adrenergic agonist: rather than raising dopamine like a stimulant, it strengthens signaling in prefrontal cortex circuits that govern attention and impulse control. It is not a controlled substance, and the trade-off is sedation and lowered blood pressure.
- Generic name
- Guanfacine (extended-release)
- Drug class
- Selective alpha-2A adrenergic agonist, non-stimulant
- Approved for
- ADHD, ages 6–17 (monotherapy or stimulant adjunct)
- Controlled?
- No — not a scheduled substance
- Onset of benefit
- Gradual; typically 1–2 weeks, full effect longer
- Common side effects
- Sleepiness, fatigue, low blood pressure, dry mouth
Compiled by DoseRoutine from public sources including NIH/MedlinePlus, the FDA label, Mayo Clinic and PubChem. Educational information, not medical advice.
Plasma half-life
Not established
Typical timing
in the evening
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Guanfacine in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Guanfacine entry is written from. Each number matches an inline marker above.
- [1]A Randomized, Placebo-Controlled Trial of Guanfacine Extended Release in Adolescents With Attention-Deficit/Hyperactivity DisorderWilens TE, Robertson B, Sikirica V, Harper L, Young JL, Bloomfield R, Lyne A, Rynkowski G, Cutler AJ · Journal of the American Academy of Child & Adolescent Psychiatry · 2015 · Peer-reviewed · PMID 26506582
- [2]Extended Release Guanfacine in Pediatric Anxiety Disorders: A Pilot, Randomized, Placebo-Controlled TrialStrawn JR, Compton SN, Robertson B, Albano AM, Hamdani M, Rynn MA · Journal of Child and Adolescent Psychopharmacology · 2017 · Peer-reviewed · PMID 28165762
References & Evidence
Sources on this page that document Guanfacine dosing, timing and safety.
- [1]U.S. National Library of Medicine View source
- [2]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Guanfacine?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Guanfacine is an alpha-2A adrenergic receptor agonist used in the management of Attention-Deficit/Hyperactivity Disorder (ADHD) and certain other conditions. It is available in both immediate-release and extended-release formulations. The extended-release formulation is marketed under the brand name Intuniv. Unlike some other ADHD medications, guanfacine is not a stimulant. It works by affecting specific receptors in the brain, which can help improve attention, reduce impulsivity, and manage hyperactivity. It is typically considered when stimulant medications are not tolerated, are ineffective, or when co-existing conditions, such as tic disorders, are present (FDA label). Guanfacine's mechanism differs from stimulants, offering an alternative approach to symptom management.
What does the research say about Guanfacine?
Tap a section to expand.
Guanfacine primarily functions as a selective alpha-2A adrenergic receptor agonist. These receptors are highly concentrated in the prefrontal cortex, a brain region critical for executive functions such as attention, working memory, and impulse control. By stimulating these receptors, guanfacine is thought to enhance synaptic signaling and strengthen the neural networks involved in these functions (DrugBank, FDA label). Specifically, activation of postsynaptic alpha-2A receptors can lead to improved neuronal firing and enhanced communication within the prefrontal cortex. This action is believed to help modulate neurotransmitter activity in these areas, particularly by affecting norepinephrine pathways, which are implicated in ADHD pathophysiology. The net effect is an improvement in regulating attention, reducing distractibility, and controlling impulsive and hyperactive behaviors.
Source for this section: Sources for How does Guanfacine work?: Jumps to this entry in the sources and references list at the end of the page.
Guanfacine is primarily recognized for its benefits in treating Attention-Deficit/Hyperactivity Disorder (ADHD). Clinical studies, as reviewed by the FDA label, indicate that guanfacine extended-release can lead to significant improvements in ADHD symptoms, including inattention, hyperactivity, and impulsivity, in children and adolescents. It is often used as a monotherapy or as an adjunctive treatment to stimulant medications.
Key benefits observed in clinical trials, as summarized by the FDA label and reviewed by organizations like the NIH National Library of Medicine (MedlinePlus), include:
* **Improved Attention:** Users may experience enhanced focus and decreased distractibility.
* **Reduced Impulsivity:** Helps in controlling impulsive behaviors and actions.
* **Decreased Hyperactivity:** Contributes to a reduction in excessive motor activity and restlessness.
* **Co-occurring Conditions:** May be particularly beneficial for individuals with ADHD who also experience tic disorders or aggression, as guanfacine can help manage these co-existing symptoms (Cochrane Review).
* **Non-Stimulant Option:** Provides an alternative treatment for individuals who do not respond well to stimulant medications or experience intolerable side effects from them.
Individual responses to guanfacine can vary, and the full therapeutic effects may take several weeks to become apparent.
The efficacy of guanfacine, particularly its extended-release formulation (Intuniv), for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD) has been established through multiple controlled clinical trials. The FDA approval of guanfacine extended-release for ADHD in children and adolescents aged 6-17 years is based on several randomized, placebo-controlled studies (FDA label).
* **Study Design:** These studies typically involved participants with a confirmed diagnosis of ADHD, who were randomized to receive either guanfacine extended-release at various doses or a placebo over several weeks.
* **Primary Endpoints:** Efficacy was primarily assessed using standardized clinician-rated scales such as the ADHD Rating Scale IV (ADHD-RS-IV), which measures symptoms of inattention and hyperactivity/impulsivity. A statistically significant reduction in ADHD-RS-IV scores was observed in participants treated with guanfacine compared to placebo (FDA label).
* **Long-Term Efficacy:** Longer-term studies and open-label extensions have also supported the sustained efficacy of guanfacine in maintaining symptom control (DrugBank).
* **Comparison to Stimulants:** While direct head-to-head comparative trials against all stimulant medications are limited, various meta-analyses and systematic reviews, including those published by Cochrane, suggest that guanfacine is an effective non-stimulant option for ADHD, with a different side effect profile compared to stimulants.
* **Impact on Co-morbidities:** Evidence suggests potential benefits in managing co-occurring conditions, such as tic disorders, in individuals with ADHD (Cochrane Review).
It is important to note that individual responses to medication can vary, and treatment decisions should always be made in consultation with a healthcare professional.
Guanfacine can cause a range of side effects, some of which are common and generally mild, while others can be more serious. The most frequently reported side effects, as detailed by the FDA label and MedlinePlus, include:
* **Drowsiness/Sedation:** This is one of the most common side effects, especially at the beginning of treatment or with dose increases. It can affect daily activities and attention.
* **Fatigue:** Feelings of tiredness or lack of energy.
* **Abdominal Pain:** Discomfort or cramping in the stomach area.
* **Nausea:** Feeling sick to the stomach.
* **Dry Mouth:** A sensation of reduced saliva.
* **Dizziness:** A feeling of lightheadedness or unsteadiness, which can increase the risk of falls.
* **Lowered Blood Pressure:** Guanfacine can cause a decrease in blood pressure, potentially leading to orthostatic hypotension (a drop in blood pressure upon standing, causing dizziness or fainting).
* **Slowed Heart Rate (Bradycardia):** A decrease in heart rate can occur.
Less common but potentially more serious side effects include significant hypotension, syncope (fainting), and severe allergic reactions. Weight gain has also been reported in some individuals. It is crucial to monitor for these effects and report any concerning symptoms to a healthcare provider.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for What are the side effects of Guanfacine?: Jumps to this entry in the sources and references list at the end of the page.
Several important warnings and precautions are associated with the use of guanfacine, as outlined by the FDA label and reviewed by organizations like MedlinePlus:
* **Cardiovascular Effects:** Guanfacine can cause dose-dependent decreases in blood pressure and heart rate. Orthostatic hypotension (a sudden drop in blood pressure when standing up) and syncope (fainting) have been reported, particularly during the initial phase of treatment or following dose increases. Caution is advised, especially in patients with pre-existing cardiovascular disease, hypotension, or conditions predisposing them to syncope. Blood pressure and heart rate should be monitored regularly.
* **Sedation and Drowsiness:** Guanfacine can cause significant sedation and drowsiness, especially when treatment is initiated or doses are increased. Patients should be cautioned about operating machinery or driving until they know how the medication affects them. Concurrent use of other central nervous system depressants, including alcohol, can exacerbate these effects.
* **Withdrawal Symptoms:** Abrupt discontinuation of guanfacine, particularly after prolonged use or at higher doses, can lead to withdrawal symptoms. These may include a rebound increase in blood pressure, nervousness, anxiety, and tachycardia. It is recommended to gradually taper the dose when discontinuing treatment.
* **Renal and Hepatic Impairment:** Dosage adjustments may be necessary in patients with significant renal or hepatic impairment, as guanfacine is primarily metabolized by the liver and excreted by the kidneys (DrugBank).
* **Risk of Overdose:** Overdose can lead to severe hypotension, bradycardia, lethargy, and respiratory depression. Medical attention is required immediately in case of suspected overdose.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for Who should avoid Guanfacine?: Jumps to this entry in the sources and references list at the end of the page.
Guanfacine is contraindicated in individuals with known hypersensitivity to guanfacine or any component of the formulation. While specific absolute contraindications beyond hypersensitivity are not universally listed, certain clinical conditions warrant extreme caution or make the use of guanfacine generally inappropriate, based on guidance from the FDA label and established medical practice:
* **Severe Cardiovascular Disease:** Patients with severe bradycardia, advanced atrioventricular block, or uncompensated heart failure may be at increased risk of adverse cardiovascular events due to guanfacine's effects on heart rate and blood pressure.
* **Recent Myocardial Infarction:** Use immediately after a myocardial infarction should be carefully considered due to potential cardiovascular instability.
* **Severe Renal or Hepatic Impairment:** While not an absolute contraindication, severe impairment in kidney or liver function may require considerable dose adjustments and careful monitoring, making its use complex and potentially risky without close clinical oversight (DrugBank).
It is essential for a clinician to assess the patient's full medical history and current health status before prescribing guanfacine.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for When should Guanfacine not be taken?: Jumps to this entry in the sources and references list at the end of the page.
Combining guanfacine with certain other substances can increase the risk of adverse effects or alter its efficacy. Particular caution should be exercised with the following, as per the FDA label and pharmacological reviews:
* **Central Nervous System (CNS) Depressants:** Concomitant use with alcohol, benzodiazepines, barbiturates, opioids, sedating antihistamines, or other sedatives can potentiate the sedative effects of guanfacine, leading to increased drowsiness, dizziness, and impaired coordination. This combination can pose a significant risk, especially when driving or operating machinery.
* **Antihypertensive Medications:** Given that guanfacine itself lowers blood pressure, co-administration with other antihypertensive agents (e.g., diuretics, beta-blockers, ACE inhibitors, calcium channel blockers) can result in an additive hypotensive effect, potentially leading to excessive drops in blood pressure, orthostatic hypotension, and syncope. Careful monitoring of blood pressure and heart rate is crucial.
* **CYP3A4 Inhibitors and Inducers:** Guanfacine is metabolized by the cytochrome P450 3A4 (CYP3A4) enzyme. Strong inhibitors of CYP3A4 (e.g., ketoconazole, clarithromycin, grapefruit juice) can increase guanfacine levels in the body, potentially enhancing its side effects. Conversely, strong inducers of CYP3A4 (e.g., rifampin, carbamazepine, St. John's Wort) can decrease guanfacine levels, potentially reducing its efficacy. Dosage adjustments may be necessary with concomitant use.
* **QT Prolonging Agents:** While not a primary effect of guanfacine, caution is advised when combining with other medications known to prolong the QT interval, especially in individuals with predispositions to arrhythmias, as there is a theoretical risk of additive cardiac effects (DrugBank).
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for What should you not mix with Guanfacine?: Jumps to this entry in the sources and references list at the end of the page.
Guanfacine, particularly its extended-release formulation (Intuniv), is commonly studied with once-daily administration. For many individuals, healthcare providers suggest taking guanfacine at bedtime. This recommendation is often made to mitigate the common side effect of drowsiness and sedation, allowing these effects to occur primarily during sleep. Taking it at bedtime may also help with consistent adherence and minimize interference with daytime activities.
However, in some clinical contexts, and depending on individual response and tolerability, it may be taken in the morning (FDA label). The decision regarding the optimal timing should be made by a licensed clinician based on the individual’s specific needs, side effect profile, and therapeutic goals. Guanfacine's long half-life of approximately 17 hours (PubChem) supports once-daily dosing, as it provides sustained therapeutic concentrations throughout a 24-hour period (DrugBank). It can be taken either with or without food, as food does not significantly impact its absorption (FDA label).
Source for this section: Sources for When should you take Guanfacine?: Jumps to this entry in the sources and references list at the end of the page.
Put it into practice
Reading about Guanfacine is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.
What interacts with Guanfacine?
Frequently asked questions about Guanfacine
While some individuals may experience initial improvements within a few days, the full therapeutic effects of guanfacine, especially for ADHD symptoms, often take several weeks to become apparent. Consistent daily use as prescribed is important for achieving optimal benefits, as detailed by the FDA label.
No, abrupt discontinuation of guanfacine is generally not recommended, particularly after prolonged use or at higher doses. Doing so can lead to withdrawal symptoms such as a rebound increase in blood pressure, nervousness, and anxiety. If guanfacine needs to be stopped, it should be done gradually under the supervision of a licensed clinician through a tapering schedule, as advised by MedlinePlus.
No, guanfacine is not classified as a controlled substance by the DEA in the United States. Unlike stimulant medications used for ADHD, it does not carry a risk of abuse or dependence, as noted by the FDA label.
The primary difference lies in their pharmacokinetic profiles. Immediate-release guanfacine typically needs to be taken multiple times a day due to its shorter duration of action. Extended-release guanfacine (Intuniv) is formulated to release the medication slowly over time, allowing for once-daily dosing and providing more consistent drug levels throughout the day, which often helps in managing symptoms more effectively and improving adherence (DrugBank, FDA label).
Weight gain has been reported as a potential side effect in some individuals taking guanfacine. While not as commonly cited as other side effects like drowsiness, it is an effect to monitor. Any significant or concerning changes in weight should be discussed with a healthcare provider, according to information from MedlinePlus.
Guanfacine is a medication, and interactions are possible with prescriptions, hormones, peptides and other supplements in the same routine. Because Guanfacine is usually taken in the evening, most avoidable conflicts come from what else lands in that same window. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Guanfacine with no sign-up.
Guanfacine is typically taken in the evening. Ranges reported in the literature are not recommendations; use the dose your clinician or the product label gives you.
Combining a medication like Guanfacine with TRT is usually a question of labs rather than a blanket yes or no: the ester, injection interval and any aromatase inhibitor all change the answer. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
Each peptide class carries its own profile against Guanfacine: a healing peptide raises different questions than a GLP-1 agonist or a growth-hormone secretagogue. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Guanfacine varies by protocol and formulation, so the label or prescription is what sets it. It is typically taken in the evening. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Guanfacine depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Guanfacine the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Intuniv is extended-release guanfacine dosed once daily for ADHD. Plain guanfacine (Tenex) is the immediate-release version originally marketed for high blood pressure; the two are not interchangeable milligram for milligram because the release profiles differ. This is educational information, not medical advice.
Stimulants raise dopamine and norepinephrine availability and work within an hour. Guanfacine instead binds postsynaptic alpha-2A receptors in the prefrontal cortex and builds effect over weeks. It is not controlled, does not suppress appetite the way stimulants do, and tends to help more with hyperactivity, irritability and emotional dysregulation than with pure focus. This is educational information, not medical advice.
Guanfacine reduces central sympathetic outflow, which lowers blood pressure and heart rate and produces sedation. Somnolence and fatigue are the most commonly reported effects in labeling, usually strongest in the first weeks and often eased by taking it in the evening under clinician guidance. This is educational information, not medical advice.
Labeling advises tapering rather than stopping abruptly, because sudden withdrawal of an alpha-2 agonist can cause rebound hypertension, headache and nervousness. Any change should be planned with the prescriber. This is educational information, not medical advice.
The ADHD trial dosed once-daily extended-release guanfacine (GXR) from 1–7 mg per day, with most participants optimized between 3–6 mg; the anxiety pilot trial flexibly dosed GXR from 1–6 mg daily. Route reported: Oral, extended-release tablet, once daily, in both cited trials. Frequency reported: Once daily dosing, flexibly titrated within each trial's protocol. These are amounts documented in the cited studies and labels for Guanfacine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- MedlinePlus(opens in a new tab)U.S. National Library of Medicine · medlineplus.gov/druginfo/meds/a601059.html
- PubChem CID 71401(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/71401
Verify at
Publisher search links for Guanfacine. These are places to check the information — they are not citations, so they are not numbered.
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Guanfacine?
Plain-text summary, safe to quote verbatim:
Intuniv is the extended-release form of guanfacine, a non-stimulant approved for ADHD in children and adolescents, alone or alongside a stimulant. It is typically taken in the evening. Dose, response, and interaction risk vary by individual, so use should be reviewed with a clinician.
Source: DoseRoutine — https://doseroutine.com/library/guanfacine
Guanfacine cheat sheet
DoseRoutine cheat sheet · Medication
Guanfacine
Intuniv is the extended-release form of guanfacine, a non-stimulant approved for ADHD in children and adolescents, alone or alongside a stimulant.
Evidence
Strong
2 human randomized trials and regulatory approval on file.
Studied range
The ADHD trial dosed once-daily extended-release guanfacine (GXR) from 1–7 mg per day, with most participants optimized between 3–6 mg; the anxiety pilot trial flexibly dosed GXR from 1–6 mg daily
Route
Oral, extended-release tablet, once daily, in both cited trials
Frequency studied
Once daily dosing, flexibly titrated within each trial's protocol
Timing
in the evening
Prescription only (US)Extended-release guanfacine (Intuniv) is FDA-approved for ADHD in children and adolescents; the currently approved maximum dose is 4 mg per day, which is lower than the highest doses reached in the cited adolescent ADHD trialUse for pediatric anxiety, as studied in the second cited trial, is not an FDA-approved indication
Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/guanfacine
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Guanfacine — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/guanfacine
What compounds are similar to Guanfacine?
Others in the medication category or studied for the same goals.