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Donepezil side effects: what 36,473 FDA adverse event reports show

Donepezil Hydrochloride · 1,186 reaction terms · 136,086 drug–reaction co-reports · data 2026-09-14
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Drug class

Acetylcholinesterase inhibitor

FDA label, Indications wording of the closest related product

Label matched

Donepezil Hydrochloride (Donepezil Hydrochloride)

closest FDA label found for this product string; brand list suppressed because the label is a related product, not an exact match

Who reports

36,473 reports · 76% serious · 5,805 with death outcome · 54% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Donepezil hydrochloride tablet is an acetylcholinesterase inhibitor indicated for the treatment of dementia of the Alzheimer's type. Efficacy has been demonstrated in patients with mild, moderate, and severe Alzheimer's Disease ( 1 ). Donepezil hydrochloride tablet is indicated for the treatment of dementia of the Alzheimer's type.

FDA label, Indications and Usage

What it is

Donepezil hydrochloride is a reversible inhibitor of the enzyme acetylcholinesterase, known chemically as (±)-2, 3-dihydro-5, 6-dimethoxy-2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1 H -inden-1-one hydrochloride. Donepezil hydrochloride is commonly referred to in the pharmacological literature as E2020.

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 1Labeled (related wording) 2Likely indication confounding 4Reporting / coding artifact 2Not in label — unassessed 31
What the badges mean

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, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,146 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show:
ReactionReportsPRR 95% CI · ROR · χ²/pEBGM EB05 · IC025Label screenSerious-only & strataTrial cross-check
Neuroglycopenia29210.5
137.5–322.4ROR 210.7 · calibrated p 1e-9 ✓
139.8 EB05 102.1 · IC025 +4.8
3/3 methods agree
Not in label — unassessedserious n=29 · ♀ 100% (drug 54%) · 100% cliniciannot reported in cached trials
Amaurosis fugax233160.3
138.7–185.3ROR 161.3 · calibrated p 3e-9 ✓
123.9 EB05 111.1 · IC025 +6.4
3/3 methods agree
Not in label — unassessedserious n=233 · 94% cliniciannot reported in cached trials
Superficial siderosis of central nervous system24149.3
95.3–234.1ROR 149.4 · calibrated p 2e-8 ✓
108.4 EB05 76.7 · IC025 +4.4
3/3 methods agree
Not in label — unassessed100% cliniciannot reported in cached trials
Amyloid related imaging abnormality-oedema/effusion16097.8
82.7–115.7ROR 98.3 · calibrated p 2e-7 ✓
82.8 EB05 72.6 · IC025 +5.8
3/3 methods agree
Not in label — unassessedserious n=69not reported in cached trials
Pleurothotonus13297.3
80.9–117.0ROR 97.7 · calibrated p 2e-7 ✓
82.2 EB05 71.1 · IC025 +5.7
3/3 methods agree
Not in label — unassessedserious n=128 · 100% cliniciannot reported in cached trials
Amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits12990.3
75.0–108.7ROR 90.6 · calibrated p 3e-7 ✓
77.1 EB05 66.6 · IC025 +5.6
3/3 methods agree
Not in label — unassessedserious n=49not reported in cached trials
Poriomania2378.0
50.4–120.6ROR 78.0 · calibrated p 2e-6 ✓
65.1 EB05 45.7 · IC025 +4.1
3/3 methods agree
Not in label — unassessedserious n=22 · 100% clinicianNCT00478205: 1/963 (0.1%) on Donepezil (serious AE)
Dementia alzheimer's type14754.5
46.1–64.6ROR 54.8 · calibrated p 9e-6 ✓
49.5 EB05 43.2 · IC025 +5.1
3/3 methods agree
Likely indication confounding
term in indications
serious n=136not reported in cached trials
Dementia with lewy bodies8751.2
41.1–63.7ROR 51.3 · calibrated p 1e-5 ✓
46.6 EB05 38.9 · IC025 +4.9
3/3 methods agree
Likely indication confounding
shares a disease stem with the indications wording
serious n=84 · ♀ 27% (drug 54%)not reported in cached trials
Multiple drug therapy5650.1
38.1–65.8ROR 50.2 · calibrated p 2e-5 ✓
45.4 EB05 36.3 · IC025 +4.6
3/3 methods agree
Reporting / coding artifactserious n=55 · 100% cliniciannot reported in cached trials
Peripheral circulatory failure3147.1
32.6–67.9ROR 47.1 · calibrated p 4e-5 ✓
42.5 EB05 31.3 · IC025 +4.1
3/3 methods agree
Not in label — unassessedserious n=31 · ♀ 100% (drug 54%) · 100% cliniciannot reported in cached trials
Dropped head syndrome2946.3
31.7–67.5ROR 46.3 · calibrated p 4e-5 ✓
41.8 EB05 30.5 · IC025 +4.0
3/3 methods agree
Not in label — unassessedserious n=26 · ♀ 100% (drug 54%) · 100% cliniciannot reported in cached trials
Anticholinergic syndrome10540.5
33.2–49.4ROR 40.6 · calibrated p 6e-5 ✓
37.6 EB05 32.0 · IC025 +4.7
3/3 methods agree
Not in label — unassessedserious n=105not reported in cached trials
Vascular dementia5437.9
28.8–49.9ROR 37.9 · calibrated p 1e-4 ✓
35.2 EB05 28.0 · IC025 +4.3
3/3 methods agree
Likely indication confounding
shares a disease stem with the indications wording
serious n=53 · ♀ 31% (drug 54%)not reported in cached trials
Sexually inappropriate behaviour2634.4
23.2–51.1ROR 34.4 · calibrated p 2e-4 ✓
31.8 EB05 22.8 · IC025 +3.7
3/3 methods agree
Not in label — unassessedserious n=18 · 100% cliniciannot reported in cached trials
Neurodegenerative disorder3434.0
24.0–48.0ROR 34.0 · calibrated p 2e-4 ✓
31.6 EB05 23.6 · IC025 +3.9
3/3 methods agree
Not in label — unassessedserious n=34 · ♀ 0% (drug 54%) · 100% cliniciannot reported in cached trials
Diabetic hyperosmolar coma2331.9
21.0–48.6ROR 31.9 · calibrated p 3e-4 ✓
29.6 EB05 20.8 · IC025 +3.5
3/3 methods agree
Not in label — unassessedserious n=23 · 100% cliniciannot reported in cached trials
Rapid eye movement sleep behaviour disorder2131.9
20.5–49.5ROR 31.9 · calibrated p 4e-4 ✓
29.5 EB05 20.4 · IC025 +3.4
3/3 methods agree
Not in label — unassessedserious n=18not reported in cached trials
Sick sinus syndrome5830.1
23.1–39.2ROR 30.1 · calibrated p 3e-4 ✓
28.4 EB05 22.8 · IC025 +4.1
3/3 methods agree
Not in label — unassessedserious n=57 · 100% cliniciannot reported in cached trials
Electrocardiogram pr prolongation3023.9
16.6–34.5ROR 23.9 · calibrated p 0.001 ✓
22.7 EB05 16.6 · IC025 +3.5
3/3 methods agree
Not in label — unassessedserious n=29 · ♀ 100% (drug 54%) · 100% cliniciannot reported in cached trials
Haemorrhagic stroke31423.9
21.3–26.7ROR 24.1 · calibrated p 8e-4 ✓
22.9 EB05 20.9 · IC025 +4.3
3/3 methods agree
Not in label — unassessedserious PRR 17.4not reported in cached trials
Reduced facial expression4023.9
17.4–32.7ROR 23.9 · calibrated p 0.001 ✓
22.7 EB05 17.4 · IC025 +3.6
3/3 methods agree
Not in label — unassessedserious n=39 · ♀ 100% (drug 54%) · 100% cliniciannot reported in cached trials
Dementia1,10323.7
22.3–25.1ROR 24.4 · calibrated p 8e-4 ✓
22.8 EB05 21.7 · IC025 +4.4
3/3 methods agree
Likely indication confounding
term in indications
serious PRR 17.2NCT00478205: 1/471 (0.2%) on Donepezil (serious AE)
Sinus node dysfunction5919.1
14.7–24.8ROR 19.1 · calibrated p 0.003 ✓
18.4 EB05 14.8 · IC025 +3.6
3/3 methods agree
Not in label — unassessedserious n=59 · 100% cliniciannot reported in cached trials
Delusion47918.3
16.7–20.1ROR 18.6 · calibrated p 0.003 ✓
17.8 EB05 16.5 · IC025 +4.0
3/3 methods agree
Not in label — unassessedserious PRR 12.0NCT00478205: 1/471 (0.2%) on Donepezil (serious AE)
Atrioventricular block first degree13418.2
15.3–21.6ROR 18.3 · calibrated p 0.003 ✓
17.6 EB05 15.3 · IC025 +3.8
3/3 methods agree
Not in label — unassessedserious n=130 · 100% cliniciannot reported in cached trials
Bradyarrhythmia4817.3
13.0–23.0ROR 17.3 · calibrated p 0.005 ✓
16.7 EB05 13.0 · IC025 +3.4
3/3 methods agree
Not in label — unassessedserious n=44 · 100% cliniciannot reported in cached trials
Sinus bradycardia24915.1
13.4–17.2ROR 15.2 · calibrated p 0.007 ✓
14.8 EB05 13.3 · IC025 +3.6
3/3 methods agree
Not in label — unassessedserious PRR 11.4 · 93% cliniciannot reported in cached trials
Cerebral atrophy9413.8
11.3–16.9ROR 13.8 · calibrated p 0.010 ✓
13.4 EB05 11.2 · IC025 +3.3
3/3 methods agree
Not in label — unassessedserious n=92not reported in cached trials
Hypersexuality4113.1
9.6–17.9ROR 13.1 · calibrated p 0.014 ✓
12.5 EB05 9.5 · IC025 +3.0
3/3 methods agree
Not in label — unassessedserious n=34 · ♀ 0% (drug 54%)not reported in cached trials
Ocular discomfort24213.1
11.5–14.9ROR 13.2 · calibrated p 0.012 ✓
12.8 EB05 11.5 · IC025 +3.4
3/3 methods agree
Not in label — unassessedserious n=237not reported in cached trials
Stoma site discharge6113.1
10.1–16.8ROR 13.1 · calibrated p 0.013 ✓
12.6 EB05 10.1 · IC025 +3.1
3/3 methods agree
Not in label — unassessedserious n=48 · ♀ 30% (drug 54%) · 100% consumernot reported in cached trials
Parkinsonism21012.6
11.0–14.5ROR 12.7 · calibrated p 0.014 ✓
12.3 EB05 11.0 · IC025 +3.4
3/3 methods agree
Not in label — unassessedserious PRR 10.5not reported in cached trials
Sedation complication5312.4
9.5–16.3ROR 12.4 · calibrated p 0.016 ✓
11.9 EB05 9.3 · IC025 +3.0
3/3 methods agree
Reporting / coding artifactserious n=53not reported in cached trials
Libido increased4312.4
9.2–16.8ROR 12.4 · calibrated p 0.017 ✓
11.8 EB05 9.0 · IC025 +2.9
3/3 methods agree
Not in label — unassessedserious n=29 · ♀ 28% (drug 54%)not reported in cached trials
Altered state of consciousness45312.3
11.2–13.5ROR 12.5 · calibrated p 0.015 ✓
12.1 EB05 11.1 · IC025 +3.4
3/3 methods agree
Not in label — unassessedserious PRR 9.2not reported in cached trials
Hallucination (hallucinations)1,56812.3
11.7–12.9ROR 12.8 · calibrated p 0.013 ✓
12.0 EB05 11.5 · IC025 +3.5
3/3 methods agree
Labeled adverse reaction
exact term
serious PRR 8.2NCT00478205: 1/471 (0.2%) on Donepezil (serious AE)
Chorea3612.2
8.8–17.0ROR 12.2 · calibrated p 0.019 ✓
11.5 EB05 8.5 · IC025 +2.8
3/3 methods agree
Not in label — unassessedserious n=34not reported in cached trials

Trial evidence (ClinicalTrials.gov)

✓ Trial adverse-event data found on ClinicalTrials.gov

Largest completed trials with posted results that list Donepezil as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (5 of 40 signal terms matched).

Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

ReactionReportsPRR 95% CI · ROR · χ²/pEBGM EB05 · IC025Label screenSerious-only & strataTrial cross-check
Fall3,0925.4
5.2–5.6ROR 5.8 · calibrated p 0.164
5.3 EB05 5.2 · IC025 +2.4
3/3 methods agree
Not in label — unassessedserious PRR 4.4NCT00478205: 2/471 (0.4%) on Donepezil (serious AE)
Death2,1351.4
1.4–1.5ROR 1.5 · calibrated p 0.610
1.4 EB05 1.4 · IC025 +0.4Outcome field, not a reactionserious PRR 1.1not reported in cached trials
Diarrhoea (diarrhea)1,8061.6
1.5–1.7ROR 1.6 · calibrated p 0.737
1.6 EB05 1.6 · IC025 +0.6Labeled adverse reaction
exact term
serious PRR 1.5NCT00478205: 4/963 (0.4%) on Donepezil (serious AE)
Dizziness1,8022.1
2.0–2.2ROR 2.1 · calibrated p 0.981
2.1 EB05 2.0 · IC025 +1.0
3/3 methods agree
Labeled adverse reaction
exact term
serious PRR 2.0NCT00478205: 1/471 (0.2%) on Donepezil (serious AE)
Fatigue (tiredness)1,7621.3
1.2–1.4ROR 1.3 · calibrated p 0.521
1.3 EB05 1.3 · IC025 +0.3Labeled adverse reaction
exact term
serious PRR 1.3not reported in cached trials
Nausea1,6811.2
1.2–1.3ROR 1.2 · calibrated p 0.465
1.2 EB05 1.2 · IC025 +0.2Labeled adverse reaction
exact term
serious PRR 1.3NCT00478205: 1/963 (0.1%) on Donepezil (serious AE)
Drug ineffective (drug did not work)1,6090.7
0.7–0.7ROR 0.7 · calibrated p 0.125
0.7 EB05 0.7 · IC025 -0.6
PRR-only: not supported by EBGM or IC
Reporting / coding artifactserious PRR 0.7not reported in cached trials
Hallucination (hallucinations)1,56812.3
11.7–12.9ROR 12.8 · calibrated p 0.013 ✓
12.0 EB05 11.5 · IC025 +3.5
3/3 methods agree
Labeled adverse reaction
exact term
serious PRR 8.2NCT00478205: 1/471 (0.2%) on Donepezil (serious AE)
Asthenia (weakness)1,5292.3
2.2–2.5ROR 2.4 · calibrated p 0.856
2.3 EB05 2.2 · IC025 +1.1
3/3 methods agree
Labeled adverse reaction
exact term
serious PRR 2.0NCT00478205: 2/963 (0.2%) on Donepezil (serious AE)
Somnolence (drowsiness)1,3643.9
3.7–4.1ROR 4.0 · calibrated p 0.372
3.9 EB05 3.7 · IC025 +1.9
3/3 methods agree
Labeled adverse reaction
exact term
serious PRR 3.7NCT00478205: 1/963 (0.1%) on Donepezil (serious AE)
Vomiting1,3261.6
1.5–1.7ROR 1.7 · calibrated p 0.739
1.6 EB05 1.6 · IC025 +0.6Labeled adverse reaction
exact term
serious PRR 1.6NCT00478205: 3/963 (0.3%) on Donepezil (serious AE)
Decreased appetite (loss of appetite)1,2283.1
2.9–3.2ROR 3.1 · calibrated p 0.586
3.0 EB05 2.9 · IC025 +1.5
3/3 methods agree
Not in label — unassessedserious PRR 3.0not reported in cached trials
Drug interaction1,2284.5
4.2–4.7ROR 4.6 · calibrated p 0.283
4.4 EB05 4.2 · IC025 +2.1
3/3 methods agree
Reporting / coding artifactserious PRR 3.5not reported in cached trials
Dyspnoea (shortness of breath)1,1201.1
1.1–1.2ROR 1.1 · calibrated p 0.402
1.1 EB05 1.1 · IC025 +0.1Not in label — unassessedserious PRR 1.1NCT00478205: 1/471 (0.2%) on Donepezil (serious AE)

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.

✓ A hand-written Bradford Hill causality assessment exists for this drug: Donepezil (cholinesterase inhibitors) ↔ Bradycardia / syncope.

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 Donepezil?

In FDA FAERS, the most frequently co-reported reaction terms for Donepezil are fall, confusional state, diarrhoea, dizziness, fatigue, nausea. 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 Donepezil have an FDA boxed warning?

No. The FDA label retrieved for Donepezil has no boxed warning; see the label's Warnings and Precautions for the recognised risks.

Do FAERS signals prove that Donepezil 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

Page generated 2026-10-14. 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.