Drug · FAERS side-effect profile with label screen
Guanfacine Hydrochloride side effects: what 4,496 FDA adverse event reports show
Drug class
Not stated in label
Brand names
Guanfacine Extended-Release
openFDA label
Who reports
4,496 reports · 56% serious · 200 with death outcome · 40% female
openFDA FAERS counts, all years, deduplication not applied
Used for
Guanfacine extended-release tablets are indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) as monotherapy and as adjunctive therapy to stimulant medications . Guanfacine extended-release tablets .
FDA label, Indications and Usage
What it is
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.
FDA label, Description section
Boxed warning
None in the current label
How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation.
Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)?
That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.
Causality screen of the 40 strongest signals
Labeled adverse reaction 12Labeled (related wording) 3Likely indication confounding 1Reporting / coding artifact 7Not in label — unassessed 17
What the badges mean
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 211 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
Show:
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Sinus bradycardia | 58 | 28.1 21.7–36.3ROR 28.4 · χ² 1,479 / p <1e-300 | 27.7 EB05 22.2 · IC025 +4.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 29.6 · 96% clinician | no trial data cached |
| Aggression | 221 | 20.6 18.1–23.5ROR 21.6 · χ² 4,098 / p <1e-300 | 20.5 EB05 18.3 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 18.0 · ♀ 19% (drug 40%) | no trial data cached |
| Psychomotor hyperactivity | 65 | 18.2 14.3–23.2ROR 18.5 · χ² 1,039 / p 4e-228 | 18.1 EB05 14.7 · IC025 +3.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 16.7 · ♀ 13% (drug 40%) | no trial data cached |
| Serotonin syndrome | 53 | 12.9 9.9–16.9ROR 13.1 · χ² 571 / p 1e-126 | 12.7 EB05 10.0 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 13.4 · ♀ 66% (drug 40%) · 100% clinician | no trial data cached |
| Bradycardia (slow heart rate) | 145 | 12.8 10.9–15.0ROR 13.1 · χ² 1,558 / p <1e-300 | 12.6 EB05 11.0 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 13.2 · 96% clinician | no trial data cached |
| Intentional overdose | 168 | 12.3 10.6–14.3ROR 12.8 · χ² 1,735 / p <1e-300 | 12.2 EB05 10.7 · IC025 +3.3 3/3 methods agree | Reporting / coding artifact | serious PRR 13.1 · ♀ 62% (drug 40%) · 96% clinician | no trial data cached |
| Abnormal behaviour | 102 | 11.9 9.9–14.5ROR 12.2 · χ² 1,012 / p 3e-222 | 11.8 EB05 9.9 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 8.1 | no trial data cached |
| Intentional self-injury | 51 | 11.8 9.0–15.5ROR 11.9 · χ² 493 / p 2e-109 | 11.5 EB05 8.9 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 12.2 | no trial data cached |
| Dystonia | 48 | 11.5 8.7–15.3ROR 11.6 · χ² 450 / p 4e-100 | 11.2 EB05 8.6 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 12.0 · ♀ 18% (drug 40%) · 91% clinician | no trial data cached |
| Sedation | 64 | 11.5 9.0–14.6ROR 11.6 · χ² 600 / p 7e-133 | 11.2 EB05 9.0 · IC025 +3.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 11.2 | no trial data cached |
| Electrocardiogram qt prolonged | 86 | 11.2 9.1–13.8ROR 11.4 · χ² 785 / p 5e-173 | 11.0 EB05 9.1 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 11.7 · 99% clinician | no trial data cached |
| Anger | 80 | 11.0 8.9–13.7ROR 11.2 · χ² 717 / p 3e-158 | 10.8 EB05 8.9 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Agitation | 150 | 9.5 8.1–11.1ROR 9.8 · χ² 1,135 / p 3e-249 | 9.4 EB05 8.1 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.8 · ♀ 17% (drug 40%) | no trial data cached |
| Neuroleptic malignant syndrome | 24 | 9.4 6.3–14.0ROR 9.5 · χ² 172 / p 1e-39 | 8.5 EB05 5.8 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 9.7 | no trial data cached |
| Irritability | 114 | 8.8 7.4–10.6ROR 9.0 · χ² 785 / p 4e-173 | 8.6 EB05 7.4 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.3 | no trial data cached |
| Orthostatic hypotension (dizziness on standing) | 33 | 8.8 6.3–12.4ROR 8.9 · χ² 221 / p 3e-50 | 8.2 EB05 6.0 · IC025 +2.4 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.3 · 94% clinician | no trial data cached |
| Respiratory depression | 23 | 8.8 5.8–13.2ROR 8.8 · χ² 150 / p 8e-35 | 7.8 EB05 5.4 · IC025 +2.2 3/3 methods agree | Labeled (related wording) related wording | serious PRR 9.3 · 100% clinician | no trial data cached |
| Affect lability | 18 | 8.7 5.5–13.8ROR 8.7 · χ² 115 / p 4e-27 | 7.5 EB05 4.9 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 9.0 | no trial data cached |
| Product substitution issue | 104 | 8.4 7.0–10.2ROR 8.6 · χ² 675 / p 4e-149 | 8.2 EB05 7.0 · IC025 +2.7 3/3 methods agree | Reporting / coding artifact | serious PRR 9.2 · 70% consumer | no trial data cached |
| Mania | 29 | 8.2 5.7–11.8ROR 8.3 · χ² 177 / p 1e-40 | 7.5 EB05 5.4 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 9.0 | no trial data cached |
| Therapy change | 17 | 8.2 5.1–13.2ROR 8.3 · χ² 101 / p 5e-24 | 7.1 EB05 4.5 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious n=4 | no trial data cached |
| Therapy partial responder | 24 | 7.4 5.0–11.1ROR 7.5 · χ² 127 / p 8e-30 | 6.7 EB05 4.6 · IC025 +2.0 3/3 methods agree | Reporting / coding artifact | serious PRR 7.7 | no trial data cached |
| Posterior reversible encephalopathy syndrome | 15 | 7.4 4.4–12.2ROR 7.4 · χ² 76 / p 1e-18 | 6.2 EB05 3.9 · IC025 +1.7 3/3 methods agree | Not in label — unassessed | serious PRR 7.1 | no trial data cached |
| Device mechanical issue | 20 | 7.2 4.7–11.2ROR 7.3 · χ² 101 / p 4e-24 | 6.3 EB05 4.3 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | – | no trial data cached |
| Emotional disorder | 46 | 6.9 5.2–9.2ROR 7.0 · χ² 227 / p 1e-51 | 6.5 EB05 5.1 · IC025 +2.2 3/3 methods agree | Not in label — unassessed | serious PRR 7.9 · ♀ 17% (drug 40%) | no trial data cached |
| Generalised tonic-clonic seizure | 23 | 6.6 4.4–9.9ROR 6.6 · χ² 103 / p 2e-24 | 5.9 EB05 4.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 6.2 | no trial data cached |
| Bipolar disorder | 15 | 6.4 3.9–10.6ROR 6.4 · χ² 63 / p 1e-15 | 5.4 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 7.0 | no trial data cached |
| Increased appetite | 25 | 6.2 4.2–9.2ROR 6.2 · χ² 104 / p 1e-24 | 5.6 EB05 4.0 · IC025 +1.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.3 | no trial data cached |
| Lethargy | 75 | 6.1 4.9–7.6ROR 6.2 · χ² 314 / p 1e-70 | 5.9 EB05 4.8 · IC025 +2.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.5 | no trial data cached |
| Hallucination, auditory | 20 | 5.9 3.8–9.1ROR 5.9 · χ² 76 / p 2e-18 | 5.2 EB05 3.6 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 6.3 | no trial data cached |
| Mood swings | 40 | 5.9 4.3–8.0ROR 5.9 · χ² 156 / p 4e-36 | 5.5 EB05 4.2 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.1 | no trial data cached |
| Toxicity to various agents | 205 | 5.7 5.0–6.5ROR 5.9 · χ² 795 / p 3e-175 | 5.6 EB05 5.0 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 6.0 · 98% clinician | no trial data cached |
| Product dispensing error | 26 | 5.6 3.8–8.2ROR 5.6 · χ² 93 / p 2e-22 | 5.1 EB05 3.7 · IC025 +1.7 3/3 methods agree | Reporting / coding artifact | serious n=4 | no trial data cached |
| Rebound effect | 13 | 5.3 3.1–9.2ROR 5.4 · χ² 42 / p 5e-11 | 4.6 EB05 2.8 · IC025 +1.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 7.5 | no trial data cached |
| Somnolence (drowsiness) | 225 | 5.2 4.6–5.9ROR 5.4 · χ² 770 / p 8e-170 | 5.2 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.3 | no trial data cached |
| Suicide attempt | 68 | 5.2 4.1–6.6ROR 5.3 · χ² 228 / p 7e-52 | 5.0 EB05 4.1 · IC025 +1.9 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Salivary hypersecretion | 11 | 5.1 2.8–9.3ROR 5.1 · χ² 33 / p 6e-9 | 4.3 EB05 2.6 · IC025 +1.1 3/3 methods agree | Not in label — unassessed | serious PRR 5.2 | no trial data cached |
| Muscle rigidity | 13 | 5.1 2.9–8.7ROR 5.1 · χ² 39 / p 3e-10 | 4.4 EB05 2.7 · IC025 +1.2 3/3 methods agree | Not in label — unassessed | serious PRR 5.4 | no trial data cached |
| Initial insomnia | 11 | 5.0 2.8–9.1ROR 5.0 · χ² 32 / p 9e-9 | 4.2 EB05 2.5 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious n=6 | no trial data cached |
| Presyncope (near-fainting) | 26 | 5.0 3.4–7.4ROR 5.0 · χ² 80 / p 2e-19 | 4.6 EB05 3.3 · IC025 +1.6 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.3 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Drug ineffective (drug did not work) | 546 | 1.9 1.8–2.1ROR 2.1 · χ² 261 / p 4e-59 | 1.9 EB05 1.8 · IC025 +0.8 | Reporting / coding artifact | serious PRR 2.6 | no trial data cached |
| Somnolence (drowsiness) | 225 | 5.2 4.6–5.9ROR 5.4 · χ² 770 / p 8e-170 | 5.2 EB05 4.6 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.3 | no trial data cached |
| Aggression | 221 | 20.6 18.1–23.5ROR 21.6 · χ² 4,098 / p <1e-300 | 20.5 EB05 18.3 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 18.0 · ♀ 19% (drug 40%) | no trial data cached |
| Toxicity to various agents | 205 | 5.7 5.0–6.5ROR 5.9 · χ² 795 / p 3e-175 | 5.6 EB05 5.0 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 6.0 · 98% clinician | no trial data cached |
| Hypotension (low blood pressure) | 185 | 4.3 3.7–5.0ROR 4.5 · χ² 471 / p 1e-104 | 4.3 EB05 3.8 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.3 · 91% clinician | no trial data cached |
| Insomnia (trouble sleeping) | 172 | 3.0 2.6–3.5ROR 3.1 · χ² 231 / p 2e-52 | 3.0 EB05 2.6 · IC025 +1.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 3.6 | no trial data cached |
| Anxiety | 171 | 2.8 2.4–3.2ROR 2.9 · χ² 198 / p 3e-45 | 2.8 EB05 2.4 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.8 | no trial data cached |
| Intentional overdose | 168 | 12.3 10.6–14.3ROR 12.8 · χ² 1,735 / p <1e-300 | 12.2 EB05 10.7 · IC025 +3.3 3/3 methods agree | Reporting / coding artifact | serious PRR 13.1 · ♀ 62% (drug 40%) · 96% clinician | no trial data cached |
| Drug interaction | 155 | 4.6 3.9–5.3ROR 4.7 · χ² 430 / p 1e-95 | 4.5 EB05 3.9 · IC025 +1.9 3/3 methods agree | Reporting / coding artifact | serious PRR 4.9 · 92% clinician | no trial data cached |
| Agitation | 150 | 9.5 8.1–11.1ROR 9.8 · χ² 1,135 / p 3e-249 | 9.4 EB05 8.1 · IC025 +2.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.8 · ♀ 17% (drug 40%) | no trial data cached |
| Bradycardia (slow heart rate) | 145 | 12.8 10.9–15.0ROR 13.1 · χ² 1,558 / p <1e-300 | 12.6 EB05 11.0 · IC025 +3.3 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 13.2 · 96% clinician | no trial data cached |
| Weight increased (weight gain) | 122 | 2.6 2.1–3.0ROR 2.6 · χ² 115 / p 4e-27 | 2.5 EB05 2.2 · IC025 +1.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 2.9 | no trial data cached |
| Product dose omission issue | 120 | 2.0 1.6–2.3ROR 2.0 · χ² 57 / p 3e-14 | 2.0 EB05 1.7 · IC025 +0.7 | Reporting / coding artifact | serious PRR 3.2 | no trial data cached |
| Irritability | 114 | 8.8 7.4–10.6ROR 9.0 · χ² 785 / p 4e-173 | 8.6 EB05 7.4 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 10.3 | no trial data cached |
| Overdose | 111 | 2.4 2.0–2.9ROR 2.4 · χ² 89 / p 2e-21 | 2.4 EB05 2.0 · IC025 +0.9 3/3 methods agree | Reporting / coding artifact | serious PRR 2.8 | no trial data cached |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Aggression — n=221, PRR 20.6
- Serotonin syndrome — n=53, PRR 12.9
- Abnormal behaviour — n=102, PRR 11.9
- Dystonia — n=48, PRR 11.5
- Electrocardiogram qt prolonged — n=86, PRR 11.2
- Anger — n=80, PRR 11.0
- Neuroleptic malignant syndrome — n=24, PRR 9.4
- Mania — n=29, PRR 8.2
- Emotional disorder — n=46, PRR 6.9
- Generalised tonic-clonic seizure — n=23, PRR 6.6
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Guanfacine?
In FDA FAERS, the most frequently co-reported reaction terms for Guanfacine are somnolence, aggression, toxicity to various agents, hypotension, insomnia, anxiety. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Guanfacine have an FDA boxed warning?
No. The FDA label retrieved for Guanfacine has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Guanfacine causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 07797c4a-a799-436b-a77c-a2861a811a99, effective 20230523; matched on
openfda.generic_name.exact:"GUANFACINE") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 251 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.