Entacapone side effects: what 4,154 FDA adverse event reports show
Drug class
Catechol-O-Methyltransferase Inhibitor
Who reports
4,154 reports · 71% serious · 639 with death outcome · 34% female
Used for
Entacapone tablets, USP are indicated as an adjunct to levodopa and carbidopa to treat end-of-dose “wearing-off” in patients with Parkinson’s disease (see CLINICAL PHARMACOLOGY, Clinical Studies ). Entacapone tablets, USP effectiveness has not been systematically evaluated in patients with Parkinson’s disease who do not experience end-of-dose “wearing-off”.
What it is
DESCRIPTION Entacapone is available as tablets containing 200 mg entacapone USP. Entacapone is an inhibitor of catechol- O -methyltransferase (COMT), used in the treatment of Parkinson’s disease as an adjunct to levodopa and carbidopa therapy.
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.
- 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. 216 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 |
|---|---|---|---|---|---|---|
| Muscle rigidity | 152 | 65.0 55.6–76.1ROR 67.5 · χ² 9,400 / p <1e-300 | 63.7 EB05 55.6 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious PRR 54.4 | no trial data cached |
| Dyskinesia (involuntary movements) | 481 | 60.6 55.7–65.9ROR 68.4 · χ² 27,840 / p <1e-300 | 59.7 EB05 55.4 · IC025 +5.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 53.0 | no trial data cached |
| Hallucination, visual | 192 | 46.6 40.6–53.6ROR 48.8 · χ² 8,453 / p <1e-300 | 46.0 EB05 40.8 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious PRR 36.8 | no trial data cached |
| Delusion | 110 | 36.1 30.0–43.4ROR 37.1 · χ² 3,695 / p <1e-300 | 35.7 EB05 30.4 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious PRR 26.2 | no trial data cached |
| Hallucination (hallucinations) | 496 | 33.6 30.9–36.5ROR 38.0 · χ² 15,616 / p <1e-300 | 33.4 EB05 31.0 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 24.8 | no trial data cached |
| Dystonia | 123 | 32.1 27.0–38.2ROR 33.0 · χ² 3,654 / p <1e-300 | 31.8 EB05 27.3 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious PRR 26.3 · ♀ 70% (drug 34%) | no trial data cached |
| Orthostatic hypotension (dizziness on standing) | 87 | 25.3 20.5–31.1ROR 25.8 · χ² 1,997 / p <1e-300 | 25.0 EB05 20.9 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious PRR 21.9 · ♀ 58% (drug 34%) | no trial data cached |
| Nocturia (night-time urination) | 58 | 24.3 18.8–31.4ROR 24.6 · χ² 1,266 / p 1e-277 | 24.0 EB05 19.3 · IC025 +3.9 3/3 methods agree | Not in label — unassessed | serious PRR 31.5 | no trial data cached |
| Device occlusion | 60 | 21.9 17.0–28.1ROR 22.2 · χ² 1,169 / p 1e-256 | 21.6 EB05 17.4 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious n=41 · 72% consumer | no trial data cached |
| Neuroleptic malignant syndrome | 49 | 20.9 15.8–27.6ROR 21.1 · χ² 904 / p 5e-199 | 20.6 EB05 16.2 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious PRR 17.0 · 95% clinician | no trial data cached |
| Therapeutic response shortened | 116 | 18.5 15.4–22.1ROR 19.0 · χ² 1,894 / p <1e-300 | 18.3 EB05 15.7 · IC025 +3.8 3/3 methods agree | Reporting / coding artifact | serious PRR 29.2 · ♀ 62% (drug 34%) | no trial data cached |
| Psychotic disorder | 97 | 16.6 13.7–20.2ROR 17.0 · χ² 1,406 / p <1e-300 | 16.5 EB05 13.9 · IC025 +3.6 3/3 methods agree | Not in label — unassessed | serious PRR 13.8 · ♀ 61% (drug 34%) | no trial data cached |
| Paranoia | 52 | 15.2 11.6–19.9ROR 15.4 · χ² 674 / p 7e-149 | 15.0 EB05 11.8 · IC025 +3.3 3/3 methods agree | Not in label — unassessed | serious PRR 12.2 | no trial data cached |
| Abnormal dreams | 71 | 12.9 10.3–16.3ROR 13.1 · χ² 768 / p 2e-169 | 12.7 EB05 10.4 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 20.2 | no trial data cached |
| Dementia | 71 | 12.9 10.2–16.3ROR 13.1 · χ² 767 / p 5e-169 | 12.7 EB05 10.3 · IC025 +3.2 3/3 methods agree | Not in label — unassessed | serious PRR 10.8 | no trial data cached |
| Initial insomnia | 26 | 12.9 8.8–18.9ROR 13.0 · χ² 273 / p 1e-61 | 12.3 EB05 8.5 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious n=22 | no trial data cached |
| Motor dysfunction | 25 | 12.5 8.5–18.5ROR 12.6 · χ² 253 / p 3e-57 | 11.9 EB05 8.1 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 11.2 | no trial data cached |
| Joint dislocation | 26 | 12.5 8.5–18.3ROR 12.6 · χ² 263 / p 2e-59 | 11.9 EB05 8.2 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 11.0 | no trial data cached |
| Hypokinesia | 35 | 12.2 8.8–17.0ROR 12.3 · χ² 348 / p 7e-78 | 11.7 EB05 8.6 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 8.7 | no trial data cached |
| Parkinsonism | 23 | 11.9 7.9–17.9ROR 12.0 · χ² 219 / p 7e-50 | 11.2 EB05 7.5 · IC025 +2.6 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 11.2 | no trial data cached |
| Device use issue | 40 | 11.7 8.6–15.9ROR 11.8 · χ² 380 / p 7e-85 | 11.3 EB05 8.4 · IC025 +2.8 3/3 methods agree | Reporting / coding artifact | serious n=6 · 90% consumer | no trial data cached |
| Cognitive disorder | 105 | 11.4 9.5–13.8ROR 11.7 · χ² 988 / p 5e-217 | 11.3 EB05 9.5 · IC025 +3.1 3/3 methods agree | Not in label — unassessed | serious PRR 12.2 | no trial data cached |
| Poor quality sleep | 48 | 11.3 8.6–15.0ROR 11.5 · χ² 442 / p 2e-98 | 11.0 EB05 8.5 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 13.8 | no trial data cached |
| Hospice care | 22 | 11.3 7.4–17.1ROR 11.4 · χ² 196 / p 8e-45 | 10.4 EB05 6.9 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 12.7 · 86% consumer | no trial data cached |
| Delirium | 74 | 10.8 8.6–13.6ROR 11.0 · χ² 650 / p 1e-143 | 10.6 EB05 8.6 · IC025 +3.0 3/3 methods agree | Not in label — unassessed | serious PRR 8.6 | no trial data cached |
| Mania | 35 | 10.8 7.7–15.0ROR 10.9 · χ² 300 / p 2e-67 | 10.2 EB05 7.5 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 9.5 | no trial data cached |
| Psychomotor hyperactivity | 34 | 10.3 7.4–14.4ROR 10.4 · χ² 276 / p 2e-62 | 9.7 EB05 7.1 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 11.8 | no trial data cached |
| Salivary hypersecretion | 20 | 10.1 6.5–15.7ROR 10.2 · χ² 155 / p 6e-36 | 9.1 EB05 5.9 · IC025 +2.3 3/3 methods agree | Not in label — unassessed | serious PRR 8.4 · ♀ 70% (drug 34%) | no trial data cached |
| Device dislocation | 86 | 10.0 8.1–12.4ROR 10.2 · χ² 689 / p 3e-152 | 9.8 EB05 8.1 · IC025 +2.9 3/3 methods agree | Reporting / coding artifact | serious PRR 10.0 | no trial data cached |
| Aggression | 96 | 9.7 7.9–11.8ROR 9.9 · χ² 739 / p 6e-163 | 9.5 EB05 7.9 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 8.5 | no trial data cached |
| Restlessness | 68 | 9.4 7.4–11.9ROR 9.5 · χ² 501 / p 3e-111 | 9.1 EB05 7.3 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 9.3 | no trial data cached |
| Abnormal behaviour | 73 | 9.3 7.4–11.6ROR 9.4 · χ² 529 / p 2e-117 | 9.0 EB05 7.3 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 7.8 | no trial data cached |
| Balance disorder | 157 | 9.2 7.9–10.7ROR 9.5 · χ² 1,137 / p 1e-249 | 9.0 EB05 7.9 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Agitation | 132 | 9.1 7.7–10.7ROR 9.3 · χ² 940 / p 9e-207 | 8.9 EB05 7.7 · IC025 +2.8 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 7.6 | no trial data cached |
| Gait inability | 58 | 8.9 6.9–11.4ROR 9.0 · χ² 396 / p 2e-88 | 8.5 EB05 6.7 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 7.6 · 70% consumer | no trial data cached |
| Choking | 34 | 8.9 6.3–12.4ROR 8.9 · χ² 229 / p 5e-52 | 8.2 EB05 6.0 · IC025 +2.4 3/3 methods agree | Not in label — unassessed | serious PRR 5.5 · 71% consumer | no trial data cached |
| Mobility decreased | 124 | 8.8 7.4–10.4ROR 9.0 · χ² 845 / p 4e-186 | 8.6 EB05 7.4 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 9.7 | no trial data cached |
| Speech disorder | 89 | 8.6 7.0–10.5ROR 8.8 · χ² 589 / p 2e-130 | 8.3 EB05 6.9 · IC025 +2.7 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 | no trial data cached |
| Confusional state (confusion) | 270 | 8.4 7.5–9.5ROR 8.9 · χ² 1,772 / p <1e-300 | 8.3 EB05 7.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 6.7 | no trial data cached |
| Hip fracture | 52 | 8.2 6.2–10.7ROR 8.3 · χ² 321 / p 4e-72 | 7.8 EB05 6.1 · IC025 +2.5 3/3 methods agree | Not in label — unassessed | serious PRR 6.7 · 77% consumer | no trial data cached |
Trial evidence (ClinicalTrials.gov)
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 |
|---|---|---|---|---|---|---|
| Hallucination (hallucinations) | 496 | 33.6 30.9–36.5ROR 38.0 · χ² 15,616 / p <1e-300 | 33.4 EB05 31.0 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious PRR 24.8 | no trial data cached |
| Dyskinesia (involuntary movements) | 481 | 60.6 55.7–65.9ROR 68.4 · χ² 27,840 / p <1e-300 | 59.7 EB05 55.4 · IC025 +5.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 53.0 | no trial data cached |
| Fall | 475 | 7.2 6.6–7.9ROR 8.0 · χ² 2,577 / p <1e-300 | 7.2 EB05 6.6 · IC025 +2.7 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 5.6 | no trial data cached |
| Death | 345 | 2.0 1.8–2.2ROR 2.1 · χ² 185 / p 2e-42 | 2.0 EB05 1.8 · IC025 +0.8 | Outcome field, not a reaction | serious PRR 1.6 | no trial data cached |
| Confusional state (confusion) | 270 | 8.4 7.5–9.5ROR 8.9 · χ² 1,772 / p <1e-300 | 8.3 EB05 7.5 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 6.7 | no trial data cached |
| Gait disturbance | 268 | 7.1 6.3–7.9ROR 7.5 · χ² 1,398 / p <1e-300 | 7.0 EB05 6.3 · IC025 +2.6 3/3 methods agree | Not in label — unassessed | serious PRR 6.9 | no trial data cached |
| Tremor (shaking) | 265 | 8.1 7.2–9.1ROR 8.5 · χ² 1,642 / p <1e-300 | 8.0 EB05 7.2 · IC025 +2.8 3/3 methods agree | Not in label — unassessed | serious PRR 7.2 | no trial data cached |
| Somnolence (drowsiness) | 201 | 5.1 4.4–5.8ROR 5.3 · χ² 655 / p 1e-144 | 5.0 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.2 | no trial data cached |
| Constipation | 193 | 4.5 3.9–5.2ROR 4.7 · χ² 528 / p 4e-117 | 4.5 EB05 4.0 · IC025 +1.9 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 4.7 | no trial data cached |
| Hallucination, visual | 192 | 46.6 40.6–53.6ROR 48.8 · χ² 8,453 / p <1e-300 | 46.0 EB05 40.8 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious PRR 36.8 | no trial data cached |
| Insomnia (trouble sleeping) | 157 | 3.0 2.5–3.5ROR 3.0 · χ² 206 / p 5e-47 | 3.0 EB05 2.6 · IC025 +1.3 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.1 | no trial data cached |
| Balance disorder | 157 | 9.2 7.9–10.7ROR 9.5 · χ² 1,137 / p 1e-249 | 9.0 EB05 7.9 · IC025 +2.9 3/3 methods agree | Not in label — unassessed | serious PRR 8.8 | no trial data cached |
| Anxiety | 153 | 2.7 2.3–3.2ROR 2.8 · χ² 165 / p 4e-38 | 2.7 EB05 2.4 · IC025 +1.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.5 | no trial data cached |
| Muscle rigidity | 152 | 65.0 55.6–76.1ROR 67.5 · χ² 9,400 / p <1e-300 | 63.7 EB05 55.6 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious PRR 54.4 | no trial data cached |
| Urinary tract infection (bladder infection) | 143 | 4.2 3.6–5.0ROR 4.4 · χ² 354 / p 2e-79 | 4.2 EB05 3.6 · IC025 +1.8 3/3 methods agree | Labeled (related wording) related wording | serious PRR 3.8 | 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.
- Muscle rigidity — n=152, PRR 65.0
- Hallucination, visual — n=192, PRR 46.6
- Delusion — n=110, PRR 36.1
- Hallucination — n=496, PRR 33.6
- Dystonia — n=123, PRR 32.1
- Orthostatic hypotension — n=87, PRR 25.3
- Nocturia — n=58, PRR 24.3
- Neuroleptic malignant syndrome — n=49, PRR 20.9
- Psychotic disorder — n=97, PRR 16.6
- Paranoia — n=52, PRR 15.2
✓ A hand-written Bradford Hill causality assessment exists for this drug: Entacapone ↔ Dyskinesia.
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 Entacapone?
In FDA FAERS, the most frequently co-reported reaction terms for Entacapone are hallucination, dyskinesia, fall, confusional state, gait disturbance, tremor. 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 Entacapone have an FDA boxed warning?
No. The FDA label retrieved for Entacapone has no boxed warning; see the label's Warnings and Precautions for the recognised risks.
Do FAERS signals prove that Entacapone 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 1fab63f2-9257-6998-5658-7e98db51b184, effective 20260108; matched on
openfda.generic_name.exact:"ENTACAPONE") - 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, 256 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.