Reported Reactions

Drugs › Central alpha-2 adrenergic agonist

Brand name · Guanfacine

Intuniv: adverse event reports filed with FDA

2,180 reports list it as a suspect or interacting product, 2009–2026. Class: Central alpha-2 adrenergic agonist.

2,180
reports as suspect product
0% of all reports · about 131 a year
48
reports, 12 months to June 2026
104 in the 12 months before
75.8%
marked serious by the reporter
75.5% across the class
1.4%
record death among outcomes, as reported
30 reports · not verified by FDA

2,180 adverse event reports received by FDA list the brand name Intuniv (guanfacine) as a suspect or interacting product, from November 2009 to June 2026. A further 1,198 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 48 reports listed it, down 54% from 104 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 131 reports a year and 0% of the 20,646,523 reports in the database, and 6.9% of the reports for the central alpha-2 adrenergic agonist class. How many people take it is not in the data, so a count is not a rate of occurrence.

Reporters most often recorded somnolence (10.3%), electrocardiogram QT prolonged (6.3%) and drug ineffective (6.1%). A report can list several reactions, so shares add to more than 100%; 350 different terms appear across these reports. Somnolence is recorded in 10.3% of these reports, a larger share than in the median central alpha-2 adrenergic agonist drug (2.6%).

75.8% of the reports are marked serious by the reporter (75.5% across the class); 1.4% record death among the outcomes and 20.3% record hospitalisation, as reported. 43% of the reports came from physicians, and the largest patient age group is 2 to 11 (25.5%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

01835Jul 2021: 13Aug 2021: 3Sep 2021: 16Oct 2021: 16Nov 2021: 13Dec 2021: 92022Jan 2022: 6Feb 2022: 8Mar 2022: 14Apr 2022: 18May 2022: 12Jun 2022: 12Jul 2022: 20Aug 2022: 14Sep 2022: 8Oct 2022: 9Nov 2022: 12Dec 2022: 212023Jan 2023: 7Feb 2023: 11Mar 2023: 14Apr 2023: 9May 2023: 8Jun 2023: 8Jul 2023: 15Aug 2023: 10Sep 2023: 13Oct 2023: 8Nov 2023: 15Dec 2023: 192024Jan 2024: 20Feb 2024: 13Mar 2024: 11Apr 2024: 12May 2024: 20Jun 2024: 35Jul 2024: 19Aug 2024: 6Sep 2024: 14Oct 2024: 8Nov 2024: 11Dec 2024: 72025Jan 2025: 7Feb 2025: 8Mar 2025: 6Apr 2025: 10May 2025: 5Jun 2025: 3Jul 2025: 1Aug 2025: 6Sep 2025: 6Oct 2025: 7Nov 2025: 4Dec 2025: 22026Jan 2026: 6Feb 2026: 3Mar 2026: 8Apr 2026: 2May 2026: 0Jun 2026: 3

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

0881762009: 1020092010: 852011: 15220112012: 812013: 8920132014: 1662015: 15220152016: 1162017: 12120172018: 1582019: 16320192020: 1632021: 17020212022: 1542023: 13720232024: 1762025: 6520252026: 22

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Intuniv reports recording the termmedian drug in central alpha-2 adrenergic agonist

  1. Somnolencedrowsiness10.3%225
  2. Electrocardiogram QT prolongeda QT prolongation on the ECG6.3%138
  3. Drug ineffectivethe medicine did not work as expected6.1%134
  4. Syncopefainting5.9%128
  5. Suicidal ideationthoughts of suicide5.6%123
  6. Bradycardiaslow heart rate5.5%120
  7. Hypotensionlow blood pressure5.1%111
  8. Dizzinesslight-headedness or unsteadiness5%109
  9. Off label useused for a purpose or in a way not on the label4.6%101
  10. Aggressionaggressive behaviour4.6%100
  11. Fatiguetiredness4.4%97
  12. Blood pressure decreaseda low blood pressure reading4.2%92
  13. Intentional overdosea deliberate overdose4.1%89
  14. Insomniadifficulty sleeping3.3%73
  15. Headachehead pain3.3%72
  16. Abnormal behaviourunusual behaviour2.9%64
  17. Product use issuea problem in how the product was used2.9%64
  18. No adverse eventno adverse event was reported2.6%57
  19. Vomitingbeing sick2.6%56
  20. Anxietyanxiety2.5%55
  21. Loss of consciousnesspassing out2.5%54
  22. Inappropriate schedule of drug administrationthe medicine was taken at the wrong times2.4%53
  23. Decreased appetitereduced appetite2%44
  24. Malaisegeneral feeling of being unwell2%43
  25. Nauseafeeling sick1.8%39
  26. Suicide attempta suicide attempt1.7%38
  27. Weight increasedweight gain1.7%38
  28. Anger1.7%37
  29. Disturbance in attentiondifficulty concentrating1.7%36

Top 30 of 350 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 13 drugs in the central alpha-2 adrenergic agonist class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death1.4%30
Life-threatening3.8%83
Hospitalisation (initial or prolonged)20.3%442
Disability1.5%32
Congenital anomaly0.1%3
Other serious64.7%1,411
Not serious24.2%528

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 31,745 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 20.2%4
2 to 1125.5%555
12 to 1715.1%329
18 to 449%196
45 to 643%65
65 to 740.2%5
75 and over0.1%2
Age not given47%1,024

Patient sex

Female24.1%525
Male48.4%1,055
Not given27.5%600

Who reported

Physician43%938
Pharmacist8.8%192
Other health professional10.4%226
Lawyer0.1%3
Consumer or non-health professional35.2%768
Not given2.4%53

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 49.4% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Attention deficit/hyperactivity disorder63329%
Attention deficit hyperactivity disorder49422.7%
Autism spectrum disorder110.5%
Impulsive behaviour70.3%
Autism60.3%
Oppositional defiant disorder60.3%

The indication field is filled in by the reporter and is often blank; shares are of all 2,180 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Intuniv reports
Vyvanse1898.7%
Concerta1748%
Abilify904.1%
Risperidone823.8%
Strattera622.8%
Risperdal602.8%
Melatonin562.6%
Adderall502.3%
Lisdexamfetamine dimesylate391.8%
Methylphenidate hydrochloride341.6%

Other products listed in reports where Intuniv is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasureIntunivCentral alpha-2 adrenergic agonistAll reports
Reports as suspect product2,18031,74520,646,523
Share of that pool—6.9%0%
Reports, latest 12 months48—1,332,454
Marked serious75.8%75.5%57.4%
Death recorded among outcomes, per 1,000 reports1416291
Hospitalisation recorded, per 1,000 reports203304213
Consumer-filed share35.2%27.5%45.8%
Top term, share of reportsSomnolence 10.3%median 2.6%1%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the central alpha-2 adrenergic agonist class

DrugName typeReportsLatest 12 monthsMarked serious
Clonidinegeneric11,71271379.2%
Tizanidinegeneric4,25937669.8%
Methyldopageneric2,65913895.8%
Clonidine hydrochloridegeneric1,84226077.8%
Dexmedetomidinegeneric1,65316093.2%
Guanfacinegeneric1,44521461.7%
Dexmedetomidine hydrochloridegeneric1,43613498%
Zanaflexbrand1,1661054.5%
Tizanidine hydrochloridegeneric1,05110480.3%
Clonidine transdermal systemgeneric8738615%
Catapres-TTS-1brand871018%
Precedexbrand5982078.1%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Intuniv reports

How many adverse event reports has FDA received for Intuniv?

2,180 reports list Intuniv as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 48 of them arrived in the latest 12 months. Another 1,198 list it only as a concomitant medication.

What reactions are recorded in Intuniv reports?

somnolence (10.3%), electrocardiogram QT prolonged (6.3%), drug ineffective (6.1%), syncope (5.9%) and suicidal ideation (5.6%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Intuniv was responsible.

How serious are the reports?

75.8% are marked serious by the reporter. Among the outcomes recorded, 1.4% of reports include death and 20.3% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

physician (43%), consumer or non-health professional (35.2%) and other health professional (10.4%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Intuniv rising?

48 reports in the 12 months to June 2026, down 54% from 104 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Intuniv was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Intuniv?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Intuniv as a suspect or interacting product; reports listing it only as a concomitant medication (1,198) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.