Prescription medication · Central Alpha-2 Agonist
guanfacine
Also sold as Intuniv, Tenex. Guanfacine extended-release tablets are used to treat Attention Deficit Hyperactivity Disorder (ADHD).
Data updated 2026-05-15
- 7,386
- FDA reportsLightly reported
- 5
- InteractionsFew interactions
- In shortage
- FDA status
What the data shows
guanfacine (Intuniv) is a prescription Central Alpha-2 Agonist, reported less often than most tracked drugs (7,386 FDA reports), with 5 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
guanfacine (Intuniv) is a prescription Central Alpha-2 Agonist. Guanfacine extended-release tablets are used to treat Attention Deficit Hyperactivity Disorder (ADHD).
Guanfacine extended-release tablets can help treat ADHD. It can be used alone or with stimulant medicines.
Verify with FDA → · CMS NADAC pricing →
Drug Shortage Alert
guanfacine is currently listed as to be discontinued by the FDA. Affected manufacturer: Actavis Pharma, Inc..
View all drug shortages →Drug Pricing (NADAC)
Generic Price
$0.17/unit
Generic Available
Yes (19 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Guanfacine extended-release tablets are used to treat Attention Deficit Hyperactivity Disorder (ADHD).
Common side effects
Feeling sleepy or tired, Low blood pressure, Dizziness
Key warnings
Guanfacine can cause low blood pressure, slow heart rate, and fainting.
The sections below are summarized in plain English from guanfacine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Guanfacine is a central alpha 2A-adrenergic receptor agonist. This means it works by stimulating specific receptors in the brain. By stimulating these receptors, guanfacine helps to improve attention and reduce impulsivity and hyperactivity in people with ADHD.
Side Effects (from patient reports)
Based on 7,386 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for guanfacine, by number of reports
- Somnolence
Somnolence
455 reports
- Aggression
Aggression
376 reports
- Fatigue
Fatigue
329 reports
- Hypotension
Hypotension
289 reports
- Dizziness
Dizziness
270 reports
- Headache
Headache
268 reports
- Insomnia
Insomnia
264 reports
- Suicidal Ideation
Suicidal Ideation
259 reports
- Anxiety
Anxiety
250 reports
- Bradycardia
Bradycardia
249 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for guanfacine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where guanfacine sits
guanfacine has more FDA adverse-event reports than 32% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is guanfacine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 7,386 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
7,386
Reports Mentioning Death
228
3.1% of reports — not proof of cause
Hospitalization Reports
1,757
Top Indication
Attention Deficit/Hyperactivity Disorder
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 3 | SOMNOLENCE | 455 |
| 4 | AGGRESSION | 376 |
| 5 | FATIGUE | 329 |
| 6 | HYPOTENSION | 289 |
| 7 | DIZZINESS | 270 |
| 8 | HEADACHE | 268 |
| 9 | INSOMNIA | 264 |
| 10 | SUICIDAL IDEATION | 259 |
| 11 | ANXIETY | 250 |
| 12 | BRADYCARDIA | 249 |
| 13 | NAUSEA | 245 |
| 14 | ABNORMAL BEHAVIOUR | 215 |
| 15 | TOXICITY TO VARIOUS AGENTS | 213 |
| 16 | INTENTIONAL OVERDOSE | 212 |
| 17 | ELECTROCARDIOGRAM QT PROLONGED | 211 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Guanfacine can cause low blood pressure, slow heart rate, and fainting. Tell your doctor if you have heart problems. This medicine can also cause sleepiness, so be careful driving or using heavy machinery. Stopping guanfacine suddenly can cause high blood pressure. Your doctor will slowly lower your dose when you stop taking it.
Known Drug Interactions
Table 14: Clinically Important Drug Interactions: Effect of other Drugs on Guanfacine 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...
Mechanism: Ketoconazole stops the body from breaking down guanfacine, which can cause the drug to build up to high levels.
Table 14: Clinically Important Drug Interactions: Effect of other Drugs on Guanfacine 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...
Mechanism: Fluconazole slows down how fast your body processes guanfacine, leading to higher amounts of the drug in your system.
Table 14: Clinically Important Drug Interactions: Effect of other Drugs on Guanfacine 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...
Mechanism: Rifampin causes your body to break down guanfacine much faster than normal, which can make the drug less effective.
Bosentan Guanfacine Monitor for adverse reactions.
Mechanism: Itraconazole blocks the process that clears guanfacine from your system. This leads to higher levels of the drug in your body.
7.2 Drugs Having No Clinically Important Interactions with Lisdexamfetamine Dimesylate Capsules From a pharmacokinetic perspective, no dose adjustment of lisdexamfetamine dimesylate capsules is necessary when lisdexamfetamine dimesylate capsules is co-administered with guanfacine, venlafaxine, or omeprazole. In addition, no dose adjustment of guanfacine or venlafaxine is needed when lisdexamfetamine dimesylate capsules is co-administered [see Clinical Pharmacology (12.3) ] .
Mechanism: These two drugs do not change how the body processes each other. They can be used together without affecting the amount of medicine in your blood.
This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.
Common Questions
Can I crush the tablet?
Can I take this with food?
What should I do if I feel dizzy?
Can I drive while taking this medicine?
What happens if I stop taking it suddenly?
How often should my blood pressure be checked?
What if I am taking other medications?
Can this medication cause heart problems?
What is the starting dose?
How will my dose be adjusted?
What are the common side effects of guanfacine?
Does guanfacine interact with other medications?
What drug class is guanfacine?
What pregnancy or breastfeeding source fields are listed for guanfacine?
Is guanfacine currently in shortage?
Related Medications in Central Alpha-2 Agonist
Other drugs grouped near guanfacine - same-class peers and common alternatives.
acamprosate
Campral
Acamprosate is a medicine that can help you stay away from alcohol if you are alcohol-dependent and have already stopped drinking.
Compare with guanfacine →
alprazolam
Xanax
Alprazolam (Xanax) is a medication that can help you with anxiety and panic disorders.
Compare with guanfacine →
amitriptyline
Elavil
Amitriptyline is a medicine used to treat depression.
Compare with guanfacine →
amphetamine/dextroamphetamine
Adderall, Adderall XR
Adderall XR is a stimulant medicine.
Compare with guanfacine →
aripiprazole
Abilify
Aripiprazole (Abilify) is a medicine used to treat certain mental disorders and mood problems.
Compare with guanfacine →
Compare beyond drug class
Nationwide peers by FAERS volume & death-report share
Two PlainMeds-derived comparison paths for guanfacine: nearest FDA FAERS report volume and nearest death-report share among drugs with at least 1,000 logged reports, excluding same-class neighbors listed above. Counts reflect reporting volume, not proven individual harm.
Similar FAERS report volume
Nearest drugs by total FAERS reports. This record: 7,386.
Similar death-report share
Nearest drugs by FAERS death-report share. This record: 3.09%.
- conjugated estrogens Δ 0.01 pts · 57,675 reports · Conjugated Estrogen 3.08%death share
- netarsudil Δ 0.03 pts · 1,797 reports · Rho Kinase Inhibitor (Ophthalmic) 3.12%death share
- biotin Δ 0.04 pts · 29,879 reports · Vitamin B7 Supplement 3.05%death share
- azelastine Δ 0.04 pts · 16,672 reports · Antihistamine (Nasal) 3.13%death share
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
FDA bioequivalence and label-record context for narrow therapeutic index medicines
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for guanfacine
The FDA label for guanfacine (sold under brand names such as Intuniv, Tenex) classifies it as a prescription-only medication in the Central Alpha-2 Agonist class. Guanfacine extended-release tablets are used to treat Attention Deficit Hyperactivity Disorder (ADHD). Official labeling lists 6 commonly reported side effects, including Feeling sleepy or tired, Low blood pressure, Dizziness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 7,386 voluntary reports. The database also lists 5 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $0.17.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC). Shortage status: FDA Drug Shortages Database.
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.
Last updated: January 23, 2025
PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages