Medicine guide

Guanfacine Hydrochloride

2 mg · Tablet

Prescription only
Central alpha-2 Adrenergic Agonist

Active substance: Guanfacine
Used in: Heart, blood pressure and circulation
Made by: Amneal Pharmaceuticals of New York LLC
Source: Official label

Quoted from the official source. Not yet reviewed by Mediclarum — the leaflet in your pack is authoritative.

At a glance

Quoted from the official label · 2026-04-14

What it is

Central alpha-2 Adrenergic Agonist

Used for

Guanfacine tablets are indicated in the management of hypertension. Guanfacine may be given alone or in combination with other antihypertensive agents, especially thiazide-type diuretics.

The label’s usual adult dose

The recommended initial dose of guanfacine tablets when given alone or in combination with another antihypertensive drug is 1 mg daily given at bedtime to minimize somnolence.

Full directions ↓

Do not take it if

Guanfacine tablets are contraindicated in patients with known hypersensitivity to guanfacine hydrochloride.

All warnings ↓

Good to know

Prescription only
FDA enforcement reports list no ongoing recall, and none from the last two years, for this product code · checked 2026-10-02

98other products contain Guanfacine — compare makers, forms and strengths

Every line above is selected, not written, from the official label. Nothing is reworded. DailyMed

What it is for

Guanfacine tablets are indicated in the management of hypertension. Guanfacine may be given alone or in combination with other antihypertensive agents, especially thiazide-type diuretics.

From the official label · 2026-04-14 · DailyMed

How it works

From this product’s own US prescribing label.

Guanfacine hydrochloride is an orally active antihypertensive agent whose principal mechanism of action appears to be stimulation of central α 2 -adrenergic receptors.
By stimulating these receptors, guanfacine reduces sympathetic nerve impulses from the vasomotor center to the heart and blood vessels.

Peak level after1 h

Half-life17 h

Mostly cleared after≈ 4 daysfive half-lives — our arithmetic

The shape is a standard model drawn from the two times above, not a measurement. How fast a medicine acts and wears off also depends on the dose, the form and the person.

How it leaves the body

In individuals with normal renal function, guanfacine and its metabolites are excreted primarily in the urine.

Quoted from the prescribing label, sections “Mechanism of Action” and “Pharmacokinetics”. DailyMed · 2026-04-14

Do not take it if

Guanfacine tablets are contraindicated in patients with known hypersensitivity to guanfacine hydrochloride.

Quoted from the official label, section “Contraindications”.

How to take it

These directions are for this exact strength and form. Another one is different.

The recommended initial dose of guanfacine tablets when given alone or in combination with another antihypertensive drug is 1 mg daily given at bedtime to minimize somnolence.
If after 3 to 4 weeks of therapy 1 mg does not give a satisfactory result, a dose of 2 mg may be given, although most of the effect of guanfacine is seen at 1 mg (see CLINICAL PHARMACOLOGY ).
Higher daily doses have been used, but adverse reactions increase significantly with doses above 3 mg/day.
The frequency of rebound hypertension is low, but it can occur.
When rebound occurs, it does so after 2 to 4 days, which is delayed compared with clonidine hydrochloride.
This is consistent with the longer half-life of guanfacine.
In most cases, after abrupt withdrawal of guanfacine, blood pressure returns to pretreatment levels slowly (within 2 to 4 days) without ill effects.

Quoted from the official label, section “Dosage & Administration”.

Other warnings

General Like other antihypertensive agents, guanfacine hydrochloride should be used with caution in patients with severe coronary insufficiency, recent myocardial infarction, cerebrovascular disease, or chronic renal or hepatic failure.
Sedation Guanfacine, like other orally active central α 2 -adrenergic agonists, causes sedation or drowsiness, especially when beginning therapy.
These symptoms are dose-related (see ADVERSE REACTIONS ).
When guanfacine is used with other centrally active depressants (such as phenothiazines, barbiturates, or benzodiazepines), the potential for additive sedative effects should be considered.
Rebound Abrupt cessation of therapy with orally active central α 2 -adrenergic agonists may be associated with increases (from depressed on-therapy levels) in plasma and urinary catecholamines, symptoms of “nervousness and anxiety” and, less commonly, increases in blood pressure to levels significantly greater than those prior to therapy.
Information for Patients Patients who receive guanfacine should be advised to exercise caution when operating dangerous machinery or driving motor vehicles until it is determined that they do not become drowsy or dizzy from the medication.
Patients should be warned that their tolerance for alcohol and other CNS depressants may be diminished.
Patients should be advised not to discontinue therapy abruptly.
Laboratory Tests In clinical trials, no clinically relevant laboratory test abnormalities were identified as causally related to drug during short-term treatment with guanfacine hydrochloride.
Drug Interactions The potential for increased sedation when guanfacine is given with other CNS-depressant drugs should be appreciated.
The administration of guanfacine concomitantly with a known microsomal enzyme inducer (phenobarbital or phenytoin) to two patients with renal impairment reportedly resulted in significant reductions in elimination half-life and plasma concentration.
In such cases, therefore, more frequent dosing may be required to achieve or maintain the desired hypotensive response.
Further, if guanfacine is to be discontinued in such patients, careful tapering of the dosage may be necessary in order to
avoid rebound phenomena (see Rebound above).
Anticoagulants Ten patients who were stabilized on oral anticoagulants were given guanfacine, 1 mg/day to 2 mg/day, for 4 weeks.
No changes were observed in the degree of anticoagulation.
In several well-controlled studies, guanfacine was administered together with diuretics with no drug interactions reported.
In the long-term safety studies, guanfacine was given concomitantly with many drugs without evidence of any interactions.
The principal drugs given (number of patients in parentheses) were:
cardiac glycosides (115), sedatives and hypnotics (103), coronary vasodilators (52), oral hypoglycemics (45), cough and cold preparations (45), NSAIDs (38), antihyperlipidemics (29), antigout drugs (24), oral contraceptives (18), bronchodilators (13), insulin (10) and beta blockers (10).
Drug/Laboratory Test Interactions No laboratory test abnormalities related to the use of guanfacine hydrochloride have been identified.
Carcinogenesis, Mutagenesis, Impairment of Fertility No carcinogenic effect was observed in studies of 78 weeks in mice at doses more than 150 times the maximum recommended human dose and 102 weeks in rats at doses more than 100 times the maximum recommended human dose.
In a variety of test models, guanfacine was not mutagenic.
No adverse effects were observed in fertility studies in male and female rats.
Pregnancy Category B Administration of guanfacine to rats at 70 times the maximum recommended human dose and to rabbits at 20 times the maximum recommended human dose resulted in no evidence of harm to the fetus.
Higher doses (100 and 200 times the maximum recommended human dose in rabbits and rats respectively) were associated with reduced fetal survival and maternal toxicity.
Rat experiments have shown that guanfacine crosses the placenta.
There are, however, no adequate and well-controlled studies in pregnant women.
Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Labor and Delivery Guanfacine hydrochloride is not recommended in the treatment of acute hypertension associated with toxemia of pregnancy.
There is no information available on the effects of guanfacine on the course of labor and delivery.
Nursing Mothers It is not known whether guanfacine hydrochloride is excreted in human milk.
Because many drugs are excreted in human milk, caution should be exercised when guanfacine is administered to a nursing woman.
Experiments with rats have shown that guanfacine is excreted in the milk.
Pediatric Use Safety and effectiveness in
children under 12 years of age have not been demonstrated.
Therefore, the use of guanfacine in this age group is not recommended.
There have been spontaneous postmarketing reports of mania and aggressive behavioral changes in pediatric patients with attention-deficit hyperactivity disorder (ADHD) receiving guanfacine.
The reported cases were from a single center.
All patients had medical or family risk factors for bipolar disorder.
All patients recovered upon discontinuation of guanfacine hydrochloride.
Hallucinations have been reported in pediatric patients receiving guanfacine for treatment of attention-deficit hyperactivity disorder.
Geriatric Use Clinical studies of guanfacine did not include sufficient numbers of subjects aged 65 and over to determine whether they responded differently from younger subjects.
Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy (see CLINICAL PHARMACOLOGY:
Pharmacokinetics ).
General Like other antihypertensive agents, guanfacine hydrochloride should be used with caution in patients with severe coronary insufficiency, recent myocardial infarction, cerebrovascular disease, or chronic renal or hepatic failure.
Sedation Guanfacine, like other orally active central α 2 -adrenergic agonists, causes sedation or drowsiness, especially when beginning therapy.
These symptoms are dose-related (see ADVERSE REACTIONS ).
When guanfacine is used with other centrally active depressants (such as phenothiazines, barbiturates, or benzodiazepines), the potential for additive sedative effects should be considered.

Quoted from the official label, section “Warnings”.

If you take too much

In an emergency, call your local emergency number or a poison control centre.

Signs and Symptoms Drowsiness, lethargy, bradycardia and hypotension have been observed following overdose with guanfacine.
A 25-year-old female intentionally ingested 60 mg.
She presented with severe drowsiness and bradycardia of 45 beats/minute.
Gastric lavage was performed and an infusion of isoproterenol (0.8 mg in 12 hours) was administered.
She recovered quickly and without sequelae.
A 28-year-old female who ingested 30 mg to 40 mg developed only lethargy, was treated with activated charcoal and a cathartic, was monitored for 24 hours, and was discharged in good health.
A 2-year-old male weighing 12 kg who ingested up to 4 mg of guanfacine developed lethargy.
Gastric lavage (followed by activated charcoal and sorbitol slurry via NG tube) removed some tablet fragments within 2 hours after ingestion, and vital signs were normal.
During 24-hour observation in ICU, systolic pressure was 58 mmHg and heart rate 70 beats per minute, at 16 hours post-ingestion.
No intervention was required, and child was discharged fully recovered the next day.
Treatment of Overdosage Gastric lavage and supportive therapy as appropriate.
Guanfacine is not dialyzable in clinically significant amounts (2.4%).

Quoted from the official label, section “Overdosage”.

Misuse and dependence

No reported abuse or dependence has been associated with the administration of guanfacine hydrochloride.

Quoted from the official label, section “Drug Abuse and Dependence”.

Side effects

Adverse reactions noted with guanfacine hydrochloride are similar to those of other drugs of the central α 2 -adrenoreceptor agonist class:
dry mouth, sedation (somnolence), weakness (asthenia), dizziness, constipation, and impotence. While the reactions are common, most are mild and tend to disappear on continued dosing. Skin rash with exfoliation has been reported in a few cases; although clear cause and effect relationships to guanfacine could not be established, should a rash occur, guanfacine should be discontinued and the patient monitored appropriately. In the dose-response monotherapy study described under CLINICAL PHARMACOLOGY, the frequency of the most commonly observed adverse reactions showed a dose relationship from 0.5 mg to 3 mg as follows:
Adverse Reaction Placebo n=59 0.5 mg n=60 1 mg n=61 2 mg n=60 3 mg n=59 Dry Mouth 0% 10% 10% 42% 54% Somnolence 8% 5% 10% 13% 39% Asthenia 0% 2% 3% 7% 3% Dizziness 8% 12% 2% 8% 15% Headache 8% 8% 13% 7% 3% Impotence 0% 0% 0% 7% 3% Constipation 0% 2% 0% 5% 15% Fatigue 2% 2% 5% 8% 10% The percent of patients who dropped out because of adverse reactions are shown below for each dosage group. Placebo 0.5 mg 1 mg 2 mg 3 mg Percent Dropouts 0% 2% 5% 13% 32% The most common reasons for dropouts among patients who received guanfacine were dry mouth, somnolence, dizziness, fatigue, weakness and constipation. In the 12-week, placebo-controlled, dose-response study of guanfacine administered with 25 mg chlorthalidone at bedtime, the frequency of the most commonly observed adverse reactions showed a clear dose relationship from 0.5 mg to 3 mg as follows:
Adverse Reaction Placebo n=73 0.5 mg n=72 1 mg n=72 2 mg n=72 3 mg n=72 Dry Mouth 5 (7%) 4 (5%) 6 (8%) 8 (11%) 20 (28%) Somnolence 1 (1%) 3 (4%) 0 (0%) 1 (1%) 10 (14%) Asthenia 0 (0%) 2 (3%) 0 (0%) 2 (2%) 7 (10%) Dizziness 2 (2%) 1 (1%) 3 (4%) 6 (8%) 3 (4%) Headache 3 (4%) 4 (3%) 3 (4%) 1 (1%) 2 (2%) Impotence 1 (0%) 1 (0%) 0 (0%) 1 (1%) 3 (4%) Constipation 0 (0%) 1 (0%) 0 (0%) 1 (1%) 1 (1%) Fatigue 3 (3%) 0 (0%) 2 (3%) 5 (6%) 3 (4%) There were 41 premature terminations because of adverse reactions in this study. The percent of patients who dropped out and the dose at which the dropout occurred were as follows:
Dose Placebo 0.5 mg 1 mg 2 mg 3 mg Percent Dropouts 6.9% 4.2% 3.2% 6.9% 8.3% Reasons for dropouts among patients who received guanfacine were:
somnolence, headache, weakness, dry mouth, dizziness, impotence, insomnia, constipation, syncope, urinary incontinence, conjunctivitis, paresthesia and dermatitis. In a second 12-week placebo-controlled combination therapy study in which the dose could be adjusted upward to 3 mg per day in 1 mg increments at 3-week intervals, i.e., a setting more similar to ordinary clinical use, the most commonly recorded reactions were:
dry mouth, 47%; constipation, 16%; fatigue, 12%; somnolence, 10%; asthenia, 6%; dizziness, 6%; headache, 4%; and insomnia, 4%. Reasons for dropouts among patients who received guanfacine were:
somnolence, dry mouth, dizziness, impotence, constipation, confusion, depression and palpitations. In the clonidine/guanfacine comparison described in CLINICAL PHARMACOLOGY, the most common adverse reactions noted were as follows:
Adverse Reactions Guanfacine (n=279) Clonidine (n=278) Dry Mouth 30 % 37% Somnolence 21% 35% Dizziness 11% 8% Constipation 10% 5% Fatigue 9% 8% Headache 4% 4% Insomnia 4% 3% Adverse reactions occurring in 3% or less of patients in the three controlled trials of guanfacine hydrochloride with a diuretic were:
Cardiovascular: bradycardia, palpitations, substernal pain
Gastrointestinal: abdominal pain, diarrhea, dyspepsia, dysphagia, nausea
CNS: amnesia, confusion, depression, insomnia, libido decrease
ENT disorders: rhinitis, taste perversion, tinnitus
Eye disorders: conjunctivitis, iritis, vision disturbance
Musculoskeletal: leg cramps, hypokinesia
Respiratory: dyspnea
Dermatologic: dermatitis, pruritus, purpura, sweating
Urogenital: testicular disorder, urinary incontinence
Other:
malaise, paresthesia, paresis Adverse reaction reports tend to decrease over time. In an open-label trial of one year’s duration, 580 hypertensive subjects were given guanfacine, titrated to achieve goal blood pressure, alone (51%), with diuretic (38%), with beta blocker (3%), with diuretic plus beta blocker (6%), or with diuretic plus vasodilator (2%). The mean daily dose of guanfacine reached was 4.7 mg. Adverse Reaction Incidence of adverse reactions at any time during the study Incidence of adverse reactions at end of one year n=580 n=580 Dry Mouth 60% 15% Drowsiness 33% 6% Dizziness 15% 1% Constipation 14% 3% Weakness 5% 1% Headache 4% 0.2% Insomnia 5% 0% There were 52 (8.9%) dropouts due to adverse effects in this 1-year trial. The causes were:
dry mouth (n = 20), weakness (n = 12), constipation (n = 7), somnolence (n = 3), nausea (n = 3), orthostatic hypotension (n = 2), insomnia (n = 1), rash (n = 1), nightmares (n = 1), headache (n = 1) and depression (n = 1). Post-marketing Experience An open-label post-marketing study involving 21,718 patients was conducted to assess the safety of guanfacine hydrochloride 1 mg/day given at bedtime for 28 days. Guanfacine was administered with or without other antihypertensive agents. Adverse events reported in the postmarketing study at an incidence greater than 1% included dry mouth, dizziness, somnolence, fatigue, headache and nausea. The most commonly reported adverse events in this study were the same as those observed in controlled clinical trials. Less frequent, possibly guanfacine-related events observed in the post-marketing study and/or reported spontaneously include:
Body as a Whole: asthenia, chest pain, edema, malaise, tremor
Cardiovascular: bradycardia, palpitations, syncope, tachycardia
Central Nervous System: paresthesias, vertigo
Eye Disorders: blurred vision
Gastrointestinal System: abdominal pain, constipation, diarrhea, dyspepsia
Liver and Biliary System: abnormal liver function tests
Musculo-Skeletal System: arthralgia, leg cramps, leg pain, myalgia
Psychiatric: agitation, anxiety, confusion, depression, insomnia, nervousness
Reproductive System, Male: impotence
Respiratory System: dyspnea
Skin and Appendages: alopecia, dermatitis, exfoliative dermatitis, pruritus, rash
Special Senses: alterations in taste
Urinary System:
nocturia, urinary frequency Rare, serious disorders with no definitive cause and effect relationship to guanfacine have been reported spontaneously and/or in the postmarketing study. These events include acute renal failure, cardiac fibrillation, cerebrovascular accident, congestive heart failure, heart block, and myocardial infarction.

Quoted from the official label, section “Adverse Reactions”.

What it looks like and how it is packed

Guanfacine tablets, USP are available in 2 tablet strengths of guanfacine (as the hydrochloride salt) as follows:
Guanfacine tablets USP, 1 mg :
white, oval, flat faced, beveled edge tablet with “AN” on one side and “711” on the other side.
They are available as follows:
Bottles of 100:
NDC 53746-711-01 Guanfacine tablets USP, 2 mg :
white, oval, flat faced, beveled edge tablet with “AN” on one side and “713” on the other side.
They are available as follows:
Bottles of 100:
NDC 53746-713-01
Store at 20º to 25 ºC (68 º to 77 ºF) [see USP Controlled Room Temperature].
Dispense contents with a child-resistant closure (as required) and in a tight, light resistant container as defined in the USP.
Packaged with child-resistant closure.
To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch Manufactured by:
Amneal Pharmaceuticals Pvt.
Ltd.
Oral Solid Dosage Unit Ahmedabad 382213, INDIA Distributed by:
Amneal Pharmaceuticals LLC Bridgewater, NJ 08807 Rev. 08-2021-00

Quoted from the official label, section “How Supplied”.

What is in it

Guanfacine hydrochloride, USP is a centrally acting antihypertensive with α 2 -adrenoceptor agonist properties in tablet form for oral administration.
The chemical name of guanfacine hydrochloride, USP is N-amidino-2-(2,6-dichlorophenyl) acetamide hydrochloride and its molecular weight is 282.55.
Its structural formula is:
Guanfacine hydrochloride, USP is a white or almost white crystalline powder; sparingly soluble in water and alcohol and slightly soluble in acetone.
Each tablet contains 1.15 mg or 2.30 mg of guanfacine hydrochloride, USP equivalent to 1 mg or 2 mg of guanfacine respectively for oral administration.
In addition, each tablet contains the following inactive ingredients:
microcrystalline cellulose, pregelatinized starch, and stearic acid. 1

Quoted from the official label, section “Description”.

Ingredients people check for

Lactose, gluten, dyes, sugars and other ingredients that matter with an allergy, intolerance or diet — as this product’s FDA label lists them.

This label’s list of inactive ingredients names none of: lactose, wheat or gluten, colour dyes, sugars, sugar alcohols, alcohol (ethanol), aspartame (phenylalanine), gelatin, peanut oil, soy, parabens, sulfites, titanium dioxide.

Quoted from the FDA label. A label that does not name an ingredient is not a guarantee that the product is free of it, and formulations change. With an allergy, check the pack and ask a pharmacist.

Every version of this medicine (35)

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Details

Made by	Amneal Pharmaceuticals of New York LLC
Active substance	Guanfacine
Used in	Heart, blood pressure and circulation
Strength	2 mg
Form	Tablet
Route	Oral
Packs	100 TABLET in 1 BOTTLE
NDC	53746-713

Source: NDC Directory · 2026-09-13 · not reviewed by a clinician

Source: US Food and Drug Administration, NDC Directory. Reuse terms: US government work (FDA).

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Other strengths and forms

19 products are sold under this name. Grouped by form; a number on a strength means several companies make it.

Tablet19 products
- 1 mg10
  1 mg · 10 companies
  +2 more
- 2 mg9
  2 mg · 9 companies
  - Amneal Pharmaceuticals LLC
  - Amneal Pharmaceuticals of New York LLC · this page
  - AvPAK
  - Chartwell RX, LLC
  - NORTHSTAR RX LLC
  - REMEDYREPACK INC.
  - TWi Pharmaceuticals, Inc.
  - Unichem Pharmaceuticals (USA), Inc.
  +1 more

Same active substance

These contain the same substance. That does not mean one can replace another — ask a pharmacist.

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