Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
Quick facts
- How it is given
- oral
- Type
- human prescription drug
- Brand names
- Guanfacine extended-release
- RxNorm ID
- 862019
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
Guanfacine extended-release tablets are indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) as monotherapy and as adjunctive therapy to stimulant medications [see Clinical Studies (14 )] . Guanfacine extended-release tablets are a central alpha 2A -adrenergic receptor agonist indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) as monotherapy and as adjunctive therapy to stimulant medications ( 1 , 1 4 ).
About this medicine
Guanfacine extended-release tablets, USP are a once-daily, extended-release formulation of guanfacine hydrochloride in a matrix tablet formulation for oral administration only. The chemical designation is N -amidino-2-(2,6-dichlorophenyl) acetamide monohydrochloride. The molecular formula is C 9 H 9 Cl 2 N 3 O·HCl corresponding to a molecular weight of 282.55 g/mol. The chemical structure is: Guanfacine hydrochloride, USP is a white to off-white powder, sparingly soluble in water (approximately 1 mg/mL) and alcohol and slightly soluble in acetone. The only organic solvent in which it has relatively high solubility is methanol (>30 mg/mL). Each tablet contains guanfacine hydrochloride, USP equivalent to 1 mg, 2 mg, 3 mg, or 4 mg of guanfacine base. The tablets also contain anhydrous lactose, colloidal silicon dioxide, fumaric acid, hypromellose and magnesium stearate. In addition, the 3-mg and 4-mg tablets also contain FD&C Blue #2 and ferric oxide yellow. Dissolution test pending. spd503-chemical-stucture
How it works
12.1 Mechanism of Action Guanfacine is a central alpha 2A -adrenergic receptor agonist. Guanfacine is not a central nervous system (CNS) stimulant. The mechanism of action of guanfacine in ADHD is not known.
Who should not take it
Guanfacine extended-release tablets are contraindicated in patients with a history of a hypersensitivity reaction to guanfacine extended-release tablets or its inactive ingredients, or other products containing guanfacine. Rash and pruritus have been reported. History of hypersensitivity to guanfacine extended-release tablets, its inactive ingredients, or other products containing guanfacine ( 4 ).
Warnings and cautions
Hypotension, bradycardia, syncope: Titrate slowly and monitor vital signs frequently in patients at risk for hypotension, heart block, bradycardia, syncope, cardiovascular disease, vascular disease, cerebrovascular disease or chronic renal failure. Measure heart rate and blood pressure prior to initiation of therapy, following dose increases, and periodically while on therapy. Avoid concomitant use of drugs with additive effects unless clinically indicated. Advise patients to avoid becoming dehydrated or overheated ( 5.1 ). Sedation and somnolence: Occur commonly with guanfacine extended-release tablets. Consider the potential for additive sedative effects with CNS depressant drugs. Caution patients against operating heavy equipment or driving until they know how they respond to guanfacine extended-release tablets ( 5.2 ). Cardiac Conduction Abnormalities: May worsen sinus node dysfunction and atrioventricular (AV) block, especially in patients taking other sympatholytic drugs. Titrate slowly and monitor vital signs frequently ( 5.3 ). Rebound Hypertension: Abrupt discontinuation of guanfacine extended-release tablets can lead to clinically significant and persistent rebound hypertension. Subsequent hypertensive encephalopathy was also reported. To minimize the risk of rebound hypertension upon discontinuation, the total daily dose of guanfacine-extended released tablets should be tapered in decrements of no more than 1 mg every 3 to 7 days ( 5.4 ). 5.1 Hypotension, Bradycardia, and Syncope Treatment with guanfacine extended-release tablets can cause dose-dependent decreases in blood pressure and heart rate. Decreases were less pronounced over time of treatment. Orthostatic hypotension and syncope have been reported [see Adverse Reactions (6.1) ]. Measure heart rate and blood pressure prior to initiation of therapy, following dose increases, and periodically while on therapy. […]
Reported side effects
The following serious adverse reactions are described elsewhere in the labeling: Hypotension, bradycardia, and syncope [see Warnings and Precautions (5.1) ] Sedation and somnolence [see Warnings and Precautions (5.2) ] Cardiac conduction abnormalities [see Warnings and Precautions (5.3) ] Rebound Hypertension [see Warnings and Precautions ( 5.4 )] Most common adverse reactions (≥5% and at least twice placebo rate) in fixed-dose monotherapy ADHD trials in children and adolescents (6 to 17 years): hypotension, somnolence, fatigue, nausea, and lethargy ( 6.1 ) Flexible dose-optimization ADHD trials in children (6 to 12 years) and adolescents (13 to 17 years): somnolence, hypotension, abdominal pain, insomnia, fatigue, dizziness, dry mouth, irritability, nausea, vomiting, and bradycardia ( 6.1 ). Adjunctive treatment to psychostimulant ADHD trial in children and adolescents (6 to 17 years): somnolence, fatigue, insomnia, dizziness, and abdominal pain ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Apotex Corp. at 1-800-706-5575 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data described below reflect clinical trial exposure to guanfacine extended-release tablets in 2,825 patients. This includes 2,330 patients from completed studies in children and adolescents, ages 6 to 17 years and 495 patients in completed studies in adult healthy volunteers. The mean duration of exposure of 446 patients that previously participated in two 2-year, open-label long-term studies was approximately 10 months. […]
Interactions with other medicines
Table 14 contains clinically important drug interactions with guanfacine extended-release tablets [see Clinical Pharmacology (12.3) ]. Table 14: Clinically Important Drug Interactions: Effect of other Drugs on Guanfacine Extended-Release Tablets Concomitant Drug Name or Drug Class Clinical Rationale and Magnitude of Drug Interaction Clinical Recommendation Strong and moderate CYP3A4 inhibitors, e.g., ketoconazole, fluconazole Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in an increase in exposure Consider dose reduction [see Dosage and administration (2.7) ] Strong and moderate CYP3A4 inducers, e.g., rifampin, efavirenz Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in a decrease in exposure Consider dose increase [see Dosage and administration (2.7) ] Strong and moderate CYP3A4 inhibitors increase guanfacine exposure. Decrease guanfacine extended-release tablets to 50% of target dosage when coadministered with strong and moderate CYP3A4 inhibitors ( 2.7 ). Strong and moderate CYP3A4 inducers decrease guanfacine exposure. Based on patient response, consider titrating guanfacine extended-release tablets dosage up to double the target dosage over 1 to 2 weeks ( 2.7 ).
Use in specific groups
8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ADHD medications, including guanfacine extended-release tablets, during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for ADHD Medications at 1-866-961-2388. Risk Summary Available data with guanfacine over decades of use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. However, use of guanfacine in pregnant women over this time has been infrequent. In animal reproduction studies, rabbits and rats exposed to 3 and 4 times the maximum recommended human dose (MRHD), respectively, showed no adverse outcomes. However, higher doses were associated with reduced fetal survival and maternal toxicity (see Data). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data Reproduction studies conducted in rats have shown that guanfacine crosses the placenta. However, administration of guanfacine to rabbits and rats during organogenesis at 3 (rabbit) and 4 (rat) times the MRHD of 0.12 mg/kg/day on a mg/m 2 basis resulted in no evidence of harm to the fetus. Higher doses (13.5 times the MRHD in both rabbits and rats) were associated with reduced fetal survival and maternal toxicity. 8.2 Lactation Risk Summary There are no data on the presence of guanfacine in human milk or the effects on the breastfed infant. The effects on milk production are also unknown. Guanfacine is present in the milk of lactating rats (see Data). If a drug is present in animal milk, it is likely that the drug will be present in human milk. […]
If too much is taken
Symptoms Postmarketing reports of guanfacine overdosage indicate that hypotension, drowsiness, lethargy, and bradycardia have been observed following overdose. Initial hypertension may develop early and may be followed by hypotension. Similar symptoms have been described in voluntary reports to the American Association of Poison Control Center’s National Poison Data System. Miosis of the pupils may be noted on examination . No fatal overdoses of guanfacine have been reported in published literature. Treatment Consult a Certified Poison Control Center by calling 1-800-222-1222 for up-to-date guidance and advice. Management of guanfacine extended-release tablets overdose should include monitoring for and the treatment of initial hypertension, if that occurs, as well as hypotension, bradycardia, lethargy and respiratory depression. Children and adolescents who develop lethargy should be observed for the development of more serious toxicity including coma, bradycardia and hypotension for up to 24 hours, due to the possibility of delayed onset hypotension.
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 23 May 2023. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.