Donepezil side effects: what 36,473 FDA adverse event reports show
Drug class
Acetylcholinesterase inhibitor
Label matched
Donepezil Hydrochloride (Donepezil Hydrochloride)
Who reports
36,473 reports · 76% serious · 5,805 with death outcome · 54% female
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.
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.
Boxed warning
None in the current label
Causality screen of the 40 strongest signals
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, 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.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Neuroglycopenia | 29 | 210.5 137.5–322.4ROR 210.7 · calibrated p 1e-9 ✓ | 139.8 EB05 102.1 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious n=29 · ♀ 100% (drug 54%) · 100% clinician | not reported in cached trials |
| Amaurosis fugax | 233 | 160.3 138.7–185.3ROR 161.3 · calibrated p 3e-9 ✓ | 123.9 EB05 111.1 · IC025 +6.4 3/3 methods agree | Not in label — unassessed | serious n=233 · 94% clinician | not reported in cached trials |
| Superficial siderosis of central nervous system | 24 | 149.3 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 — unassessed | 100% clinician | not reported in cached trials |
| Amyloid related imaging abnormality-oedema/effusion | 160 | 97.8 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 — unassessed | serious n=69 | not reported in cached trials |
| Pleurothotonus | 132 | 97.3 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 — unassessed | serious n=128 · 100% clinician | not reported in cached trials |
| Cholinergic syndrome | 90 | 93.7 75.0–117.1ROR 93.9 · calibrated p 2e-7 ✓ | 79.2 EB05 66.4 · IC025 +5.5 3/3 methods agree | Labeled (related wording) related wording | serious n=90 · ♀ 32% (drug 54%) · 100% clinician | not reported in cached trials |
| Amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits | 129 | 90.3 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 — unassessed | serious n=49 | not reported in cached trials |
| Poriomania | 23 | 78.0 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 — unassessed | serious n=22 · 100% clinician | NCT00478205: 1/963 (0.1%) on Donepezil (serious AE) |
| Dementia alzheimer's type | 147 | 54.5 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=136 | not reported in cached trials |
| Dementia with lewy bodies | 87 | 51.2 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 therapy | 56 | 50.1 38.1–65.8ROR 50.2 · calibrated p 2e-5 ✓ | 45.4 EB05 36.3 · IC025 +4.6 3/3 methods agree | Reporting / coding artifact | serious n=55 · 100% clinician | not reported in cached trials |
| Peripheral circulatory failure | 31 | 47.1 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 — unassessed | serious n=31 · ♀ 100% (drug 54%) · 100% clinician | not reported in cached trials |
| Dropped head syndrome | 29 | 46.3 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 — unassessed | serious n=26 · ♀ 100% (drug 54%) · 100% clinician | not reported in cached trials |
| Anticholinergic syndrome | 105 | 40.5 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 — unassessed | serious n=105 | not reported in cached trials |
| Vascular dementia | 54 | 37.9 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 behaviour | 26 | 34.4 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 — unassessed | serious n=18 · 100% clinician | not reported in cached trials |
| Neurodegenerative disorder | 34 | 34.0 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 — unassessed | serious n=34 · ♀ 0% (drug 54%) · 100% clinician | not reported in cached trials |
| Diabetic hyperosmolar coma | 23 | 31.9 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 — unassessed | serious n=23 · 100% clinician | not reported in cached trials |
| Rapid eye movement sleep behaviour disorder | 21 | 31.9 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 — unassessed | serious n=18 | not reported in cached trials |
| Sick sinus syndrome | 58 | 30.1 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 — unassessed | serious n=57 · 100% clinician | not reported in cached trials |
| Urinary tract disorder | 212 | 28.4 24.7–32.6ROR 28.6 · calibrated p 4e-4 ✓ | 27.0 EB05 24.1 · IC025 +4.4 3/3 methods agree | Labeled (related wording) related wording | serious n=211 · 95% clinician | NCT00478205: 2/471 (0.4%) on Donepezil (serious AE) |
| Electrocardiogram pr prolongation | 30 | 23.9 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 — unassessed | serious n=29 · ♀ 100% (drug 54%) · 100% clinician | not reported in cached trials |
| Haemorrhagic stroke | 314 | 23.9 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 — unassessed | serious PRR 17.4 | not reported in cached trials |
| Reduced facial expression | 40 | 23.9 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 — unassessed | serious n=39 · ♀ 100% (drug 54%) · 100% clinician | not reported in cached trials |
| Dementia | 1,103 | 23.7 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 17.2 | NCT00478205: 1/471 (0.2%) on Donepezil (serious AE) |
| Sinus node dysfunction | 59 | 19.1 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 — unassessed | serious n=59 · 100% clinician | not reported in cached trials |
| Delusion | 479 | 18.3 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 — unassessed | serious PRR 12.0 | NCT00478205: 1/471 (0.2%) on Donepezil (serious AE) |
| Atrioventricular block first degree | 134 | 18.2 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 — unassessed | serious n=130 · 100% clinician | not reported in cached trials |
| Bradyarrhythmia | 48 | 17.3 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 — unassessed | serious n=44 · 100% clinician | not reported in cached trials |
| Sinus bradycardia | 249 | 15.1 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 — unassessed | serious PRR 11.4 · 93% clinician | not reported in cached trials |
| Cerebral atrophy | 94 | 13.8 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 — unassessed | serious n=92 | not reported in cached trials |
| Hypersexuality | 41 | 13.1 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 — unassessed | serious n=34 · ♀ 0% (drug 54%) | not reported in cached trials |
| Ocular discomfort | 242 | 13.1 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 — unassessed | serious n=237 | not reported in cached trials |
| Stoma site discharge | 61 | 13.1 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 — unassessed | serious n=48 · ♀ 30% (drug 54%) · 100% consumer | not reported in cached trials |
| Parkinsonism | 210 | 12.6 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 — unassessed | serious PRR 10.5 | not reported in cached trials |
| Sedation complication | 53 | 12.4 9.5–16.3ROR 12.4 · calibrated p 0.016 ✓ | 11.9 EB05 9.3 · IC025 +3.0 3/3 methods agree | Reporting / coding artifact | serious n=53 | not reported in cached trials |
| Libido increased | 43 | 12.4 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 — unassessed | serious n=29 · ♀ 28% (drug 54%) | not reported in cached trials |
| Altered state of consciousness | 453 | 12.3 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 — unassessed | serious PRR 9.2 | not reported in cached trials |
| Hallucination (hallucinations) | 1,568 | 12.3 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 8.2 | NCT00478205: 1/471 (0.2%) on Donepezil (serious AE) |
| Chorea | 36 | 12.2 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 — unassessed | serious n=34 | not 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).
- NCT00478205 — Comparison of 23 mg Donepezil Sustained Release (SR) to 10 mg Donepezil Immediate Release (IR) in Patients Wit (N=1467, PHASE3; 130 AE terms posted; arms: Donepezil SR 23 mg; Donepezil IR 10 mg)
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.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Fall | 3,092 | 5.4 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 — unassessed | serious PRR 4.4 | NCT00478205: 2/471 (0.4%) on Donepezil (serious AE) |
| Death | 2,135 | 1.4 1.4–1.5ROR 1.5 · calibrated p 0.610 | 1.4 EB05 1.4 · IC025 +0.4 | Outcome field, not a reaction | serious PRR 1.1 | not reported in cached trials |
| Confusional state (confusion) | 1,968 | 7.1 6.8–7.4ROR 7.4 · calibrated p 0.084 | 7.0 EB05 6.7 · IC025 +2.7 3/3 methods agree | Labeled (related wording) related wording | serious PRR 4.9 | NCT00478205: 3/471 (0.6%) on Donepezil (serious AE) |
| Diarrhoea (diarrhea) | 1,806 | 1.6 1.5–1.7ROR 1.6 · calibrated p 0.737 | 1.6 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.5 | NCT00478205: 4/963 (0.4%) on Donepezil (serious AE) |
| Dizziness | 1,802 | 2.1 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 2.0 | NCT00478205: 1/471 (0.2%) on Donepezil (serious AE) |
| Fatigue (tiredness) | 1,762 | 1.3 1.2–1.4ROR 1.3 · calibrated p 0.521 | 1.3 EB05 1.3 · IC025 +0.3 | Labeled adverse reaction exact term | serious PRR 1.3 | not reported in cached trials |
| Nausea | 1,681 | 1.2 1.2–1.3ROR 1.2 · calibrated p 0.465 | 1.2 EB05 1.2 · IC025 +0.2 | Labeled adverse reaction exact term | serious PRR 1.3 | NCT00478205: 1/963 (0.1%) on Donepezil (serious AE) |
| Drug ineffective (drug did not work) | 1,609 | 0.7 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 artifact | serious PRR 0.7 | not reported in cached trials |
| Hallucination (hallucinations) | 1,568 | 12.3 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 8.2 | NCT00478205: 1/471 (0.2%) on Donepezil (serious AE) |
| Asthenia (weakness) | 1,529 | 2.3 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 2.0 | NCT00478205: 2/963 (0.2%) on Donepezil (serious AE) |
| Somnolence (drowsiness) | 1,364 | 3.9 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 3.7 | NCT00478205: 1/963 (0.1%) on Donepezil (serious AE) |
| Vomiting | 1,326 | 1.6 1.5–1.7ROR 1.7 · calibrated p 0.739 | 1.6 EB05 1.6 · IC025 +0.6 | Labeled adverse reaction exact term | serious PRR 1.6 | NCT00478205: 3/963 (0.3%) on Donepezil (serious AE) |
| Decreased appetite (loss of appetite) | 1,228 | 3.1 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 — unassessed | serious PRR 3.0 | not reported in cached trials |
| Drug interaction | 1,228 | 4.5 4.2–4.7ROR 4.6 · calibrated p 0.283 | 4.4 EB05 4.2 · IC025 +2.1 3/3 methods agree | Reporting / coding artifact | serious PRR 3.5 | not reported in cached trials |
| Dyspnoea (shortness of breath) | 1,120 | 1.1 1.1–1.2ROR 1.1 · calibrated p 0.402 | 1.1 EB05 1.1 · IC025 +0.1 | Not in label — unassessed | serious PRR 1.1 | NCT00478205: 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.
- Neuroglycopenia — n=29, PRR 210.5
- Amaurosis fugax — n=233, PRR 160.3
- Superficial siderosis of central nervous system — n=24, PRR 149.3
- Amyloid related imaging abnormality-oedema/effusion — n=160, PRR 97.8
- Pleurothotonus — n=132, PRR 97.3
- Amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits — n=129, PRR 90.3
- Poriomania — n=23, PRR 78.0 (also seen in trial arm)
- Peripheral circulatory failure — n=31, PRR 47.1
- Dropped head syndrome — n=29, PRR 46.3
- Anticholinergic syndrome — n=105, PRR 40.5
✓ 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
- FDA label via openFDA (set ID 03e26183-3e07-45e8-a414-a8bad32483e2, effective 20241129; matched on
openfda.generic_name.exact:"DONEPEZIL HYDROCHLORIDE") - 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, 1,186 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 - ClinicalTrials.gov API v2 (query
DONEPEZIL, results-bearing studies sorted by enrollment)
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.