Medication approval journey
guanfacine (Intuniv)
Approved for ADHD in children and adolescents 6 to 17, as monotherapy or adjunct to stimulants
Before changing anything
Stopping abruptly can be dangerous — never do it without medical supervision
Clonidine and guanfacine must not be stopped abruptly — rebound high blood pressure is a real risk. Any change should be prescriber-supervised.
How long the trials actually ran
We could not establish a longest trial length for guanfacine. That is a gap in what we can show you — not evidence that the trials ran long.
The label carries a clinical studies section describing the trials the approval rested on.
The gap between how long the trials ran and how long people actually take these medications is the single most important thing on this page. It is not evidence that longer use is unsafe or ineffective. It is evidence that longer use was not what got tested.
How many Americans take guanfacine
Survey-based federal estimates, published with a lag of about two years. They count prescriptions filled, not outcomes.
- 826,201
- prescriptions in the United States (2024)
- 128,407
- people filling them (2024)
Prescriptions are down 69% since 2014. Whatever you decide about guanfacine, you are deciding alongside about 128,407 other people this year.
Source: ClinCalc DrugStats (Medical Expenditure Panel Survey (MEPS), Agency for Healthcare Research and Quality), CC BY-SA 4.0, release 2026.08.
What people report to the FDA about guanfacine
Read this before the numbers.
Anyone can file an adverse event report — patients, doctors, manufacturers — and nobody verifies that the drug caused what was reported. There is no denominator: tens of millions of prescriptions generate reports at an unknowable rate, and reporting rises with news coverage, not necessarily with harm. Counts below are report volumes, not rates, and cannot be compared between drugs. The FDA itself says not to use this data to make medical decisions — we show it because you deserve to see what is in the public record, with its limits stated plainly.
- 7,823
- reports mentioning guanfacine, all time
- 4,622
- filed as serious (a report-level flag covering every drug and outcome in the report)
Most-reported reactions
- Drug ineffective813
- Off label use630
- Somnolence471
- Aggression388
- Fatigue351
- Hypotension299
- Dizziness291
- Insomnia288
- Headache283
- Bradycardia271
“Drug ineffective” ranking this high is worth noticing: a report of not being helped counts as an adverse event too, and people file them in large numbers.
Source: FDA Adverse Event Reporting System (FAERS), via openFDA, data through 2026-07-30.
Known interactions, from the label
The FDA label’s interactions section, verbatim. A pharmacist checking your actual medication list beats any published list — including this one.
Read the label’s interactions section
7 DRUG INTERACTIONS Table 14 contains clinically important drug interactions with guanfacine extended-release tablets [see Clinical Pharmacology ( 12.3 )]. Table 14: Clinically Important Drug Interaction: 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 ).
FDA label for guanfacine, effective August 3, 2026 — DailyMed.
Who pays for guanfacine
Two claims datasets and one survey, covering different populations with different instruments — they cannot be reconciled by arithmetic, and where their sum crowds the all-payer estimate, that is a finding about the estimates rather than a percentage.
- Medicare Part D
- 46,955 beneficiaries filled 252,004 claims in 2024 — 16,545 aged 65 and over, and 30,410 under 65. The under-65 group is not a picture of ordinary working-age adults: Medicare before 65 means the disabled and dual-eligible population — among the sickest, highest-need people in the program — and reading their utilization as typical adult use would be a category error.
- Medicaid
- At least 3,999,736 prescriptions in 2024 — a floor, because 51 of 485 national data rows are suppressed for privacy and contribute zero. Medicaid covers more children than any insurer in the country and publishes no age split — how much of this number is pediatric use is not knowable from public data.
- All payers (survey estimate)
- The MEPS-based estimate above puts the whole country at 826,201 prescriptions and 128,407 people in 2024. Subtracting the public programs from it would produce a number for everyone else — and we do not print that number, because subtracting a survey from claims counts manufactures precision that does not exist.
- The population nobody counts
- The commercially insured working-age adult — statistically, the likeliest person to be reading this page — is the one population with no public per-drug count anywhere. Private claims data exists and is sold, but nothing a patient can check is published. For children the record is thinner still: no public source counts pediatric use of guanfacine specifically; the closest the public record comes is condition-level treatment rates for children, which we have traced for one condition in how childhood ADHD got counted.
Sources: Medicare Part D Prescribers — by Geography and Drug, data.cms.gov, National rows, data year 2024 (published with ~17-month lag). Medicaid State Drug Utilization Data 2024, data.medicaid.gov, national aggregate rows. Retrieved 2026-09-01.
The approval, step by step
Step 1
What the approval was actually based on
Which studies did the FDA rely on, how long did they run, and who was in them?
Efficacy of INTUNIV in the treatment of ADHD was established in children and adolescents (6 to 17 years) in: Five short-term, placebo-controlled monotherapy trials (Studies 1, 2, 4, 5, and 6). One short-term, placebo-controlled adjunctive trial with psychostimulants (Study 3). One long-term, placebo-controlled monotherapy maintenance trial (Study 7).
FDA-approved labelling, 14 CLINICAL STUDIES — read the label on DailyMed
Our reading
This entry is anchored on the extended-release product approved for ADHD in 2009 — not on immediate-release guanfacine, which is a 1986 blood-pressure drug under a different application. The same molecule, two different approvals, and only this one was ever tested for ADHD. The trial package is genuinely broader than most here: five monotherapy trials, an adjunctive trial, and a maintenance trial. The population is the catch — children and adolescents only. Adult ADHD use of guanfacine rides on extrapolation, not on this label.
Step 2
The approval
When was it approved, under what application, and by whose review?
- Approved
- September 2, 2009
- Application
- NDA022037
- Review
- STANDARD
- Original sponsor
- Shire (now Takeda)
- Holds it now
- Takeda Pharmaceuticals USA
- Label submissions since
- 12
Source: openFDA Drugs@FDA, original application ORIG-1
Step 3
What was added after it was on the market
Which warnings arrived only after millions of people were already taking it?
We have not recorded a post-approval change to the guanfacine label. That is the state of our record, not a finding that nothing was ever added.
Step 4
What independent research has found since
What has been learned by people who were not selling it?
We have not yet added independent post-approval research on guanfacine to the evidence library. Absence here means we have not covered it, not that none exists.
Step 5
What still is not known
Which questions you might reasonably have has nobody answered yet?
- Approved for ages 6 to 17. If the patient is 35, what evidence is the prescription resting on?
- Immediate-release guanfacine was never approved for ADHD. Which version is being prescribed, and does the prescriber know the difference?
- The maintenance trial is the strongest long-term evidence in the ADHD entries here — worth actually reading before assuming the others match it.
Deciding about guanfacine?
- 12 questions to ask before starting a psychiatric medication — each with the study behind it
- Already on it? The 10-question annual review — including the honest case for staying
- How long every drug here was tested before approval — one chart, all medications
Open guanfacine (Intuniv) in Resolv
The app has the full approval journey, the resources behind it, and people working through the same questions.
