pharmacopeia
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/api/v1/drug/guanfacine

Mechanism of action

Sourced from openFDA

Mechanism-of-action class: Adrenergic alpha2-Agonists.

Indications

Sourced from openFDA
  • Guanfacine tablets, USP are indicated in the management of hypertension. Guanfacine tablets, USP may be given alone or in combination with other antihypertensive agents, especially thiazide-type diuretics.ICD-10: I10

Contraindications

Sourced from openFDA
  • Guanfacine tablets are contraindicated in patients with known hypersensitivity to guanfacine hydrochloride.contraindicated

Dosage & administration

Sourced from openFDA

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 weeks 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 tablets are 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 days 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 days to 4 days) without ill effects.

Adverse reactions

Sourced from openFDA

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 tablets could not be established, should a rash occur, guanfacine tablets 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 % 13 % 7 % 5 % 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 % 2.0 % 5.0 % 13 % 32 % The most common reasons for dropouts among patients who received guanfacine were dry mouth, somnolence, dizziness, fatigue, weakness, and constipation.

Approval history

Sourced from openFDA
  • Oct 17, 1995ANDAANDA074145Watson Labs
  • Jan 27, 1997ANDAANDA074796Aurobindo Pharma Usa
  • Feb 28, 1997ANDAANDA074673Epic Pharma Llc
  • Nov 25, 1998ANDAANDA075109Amneal Pharm
  • Sep 2, 2009NDANDA022037Takeda Pharms Usa
  • Oct 5, 2012ANDAANDA200881Actavis Elizabeth
  • Jun 2, 2015ANDAANDA201408Twi Pharms
  • Nov 16, 2017ANDAANDA205689Sun Pharm

FDA shortages

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Reference statistics from the openFDA drug-shortage dataset. For a live view, consult the FDA database directly. Not clinical guidance.

  • Guanfacine Hydrochloride, Tablet, Extended Release, 1 mg (NDC 0228-2850-11)To be discontinued
    Sponsor: Actavis Pharma, Inc.
    Updated
  • Guanfacine Hydrochloride, Tablet, Extended Release, 2 mg (NDC 0228-2851-11)To be discontinued
    Sponsor: Actavis Pharma, Inc.
    Updated
  • Guanfacine Hydrochloride, Tablet, Extended Release, 3 mg (NDC 0228-2853-11)To be discontinued
    Sponsor: Actavis Pharma, Inc.
    Updated
  • Guanfacine Hydrochloride, Tablet, Extended Release, 4 mg (NDC 0228-2855-11)To be discontinued
    Sponsor: Actavis Pharma, Inc.
    Updated

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
7,600 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Drug Ineffective79710%
  2. 2Off Label Use6168.1%
  3. 3Somnolence4586.0%
  4. 4Aggression3795.0%
  5. 5Fatigue3374.4%
  6. 6Hypotension2923.8%
  7. 7Dizziness2833.7%
  8. 8Headache2723.6%
  9. 9Insomnia2703.6%
  10. 10Bradycardia2673.5%
  11. 11Suicidal Ideation2673.5%
  12. 12Anxiety2563.4%
  13. 13Nausea2513.3%
  14. 14Intentional Overdose2333.1%
  15. 15Electrocardiogram Qt Prolonged2323.1%

Literature

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Recent PubMed references pinned to Guanfacine as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 96 ClinicalTrials.gov registrations naming Guanfacine as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Guanfacine work?
Mechanism-of-action class: Adrenergic alpha2-Agonists.
What is Guanfacine used for?
According to FDA labeling, Guanfacine carries indications including: Guanfacine tablets, USP are indicated in the management of hypertension. Guanfacine tablets, USP may be given alone or in combination with other antihypertensive agents, especially thiazide-type diuretics.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Guanfacine?
Guanfacine is classified as Imidazoline receptor agonists, Central alpha-2 Adrenergic Agonist, Adrenergic alpha2-Agonists, Decreased Blood Pressure, Systemic Arterial Vasodilation, Systemic Venous Vasodilation.
What are the brand names for Guanfacine?
Guanfacine is marketed under brand names including Intuniv.
What are the contraindications for Guanfacine?
Guanfacine labeling lists contraindications including: Guanfacine tablets are contraindicated in patients with known hypersensitivity to guanfacine hydrochloride.. Always consult the full prescribing information and a clinician.
Note. Data for guanfacine is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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