guanfacine Side Effects
Also known as: Intuniv, Tenex
Analysis of 7,386 adverse event reports submitted to the FDA from 2004 to 2025.
Total Reports
7,386
Death-Related
228
3.1% of reports
Hospitalizations
1,757
23.8% of reports
Top Indication
Attention Deficit/Hyperactivity Disorder
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 228 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| COMPLETED SUICIDE | 68 |
| DEATH | 51 |
| TOXICITY TO VARIOUS AGENTS | 31 |
| HYPOTENSION | 16 |
| COMA | 13 |
| GASTROINTESTINAL HAEMORRHAGE | 13 |
| OFF LABEL USE | 13 |
| TACHYCARDIA | 13 |
| RESPIRATORY DEPRESSION | 12 |
| DEPRESSED LEVEL OF CONSCIOUSNESS | 11 |
| ELECTROCARDIOGRAM QT PROLONGED | 11 |
| AGITATION | 10 |
| CARDIAC ARREST | 10 |
| DELIRIUM | 10 |
| DRUG INTERACTION | 10 |
| ELECTROCARDIOGRAM QRS COMPLEX PROLONGED | 10 |
| OVERDOSE | 10 |
| PARAESTHESIA | 10 |
| SUSPECTED SUICIDE | 10 |
| ASTHENIA | 9 |
Reactions in Hospitalization Reports
Top reactions in 1,757 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| INTENTIONAL OVERDOSE | 181 |
| BRADYCARDIA | 175 |
| TOXICITY TO VARIOUS AGENTS | 169 |
| HYPOTENSION | 164 |
| DRUG INEFFECTIVE | 128 |
| OFF LABEL USE | 127 |
| SOMNOLENCE | 123 |
| OVERDOSE | 106 |
| DRUG INTERACTION | 99 |
| VOMITING | 92 |
| SUICIDE ATTEMPT | 89 |
| AGGRESSION | 84 |
| AGITATION | 83 |
| DIZZINESS | 78 |
| NAUSEA | 73 |
| ELECTROCARDIOGRAM QT PROLONGED | 72 |
| HYPERTENSION | 72 |
| SINUS BRADYCARDIA | 64 |
| CONDITION AGGRAVATED | 62 |
| HEADACHE | 62 |
Nearby — Related Medications
What the FAERS Data Reveals About guanfacine Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 7,386 voluntary reports linked to guanfacine and its brand equivalents (Intuniv, Tenex), spanning 2004 through 2025. Of those, 228 (3.1%) listed death as an outcome and 1,757 (23.8%) involved hospitalization. The most common indication reported alongside adverse events was Attention Deficit/Hyperactivity Disorder.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 36% were female and 62% male; age distribution skews toward 0-17, with 3,034 reports in that bracket. The single most reported reaction is drug ineffective with 778 submissions, followed by off label use and somnolence.
FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice — speak with a licensed clinician about any side-effect concerns.
Read our methodology — how this data is sourced, computed, and verified.