Drug · FAERS side-effect profile with label screen

Carbidopa and Levodopa side effects: what 47,172 FDA adverse event reports show

Carbidopa And Levodopa · 1,210 reaction terms · 172,360 drug–reaction co-reports · data 2026-09-14

Drug class

Aromatic Amino Acid Decarboxylation Inhibitor

FDA label (Established Pharmacologic Class) of the closest related product

Label matched

Carbidopa (Carbidopa)

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

Who reports

47,172 reports · 55% serious · 5,930 with death outcome · 43% female

openFDA FAERS counts, all years, deduplication not applied

Used for

Carbidopa tablets are indicated for use with carbidopa-levodopa or with levodopa in the treatment of the symptoms of idiopathic Parkinson's disease (paralysis agitans), postencephalitic parkinsonism, and symptomatic parkinsonism, which may follow injury to the nervous system by carbon monoxide intoxication and/or manganese intoxication.

FDA label, Indications and Usage

What it is

DESCRIPTION Carbidopa, an inhibitor of aromatic amino acid decarboxylation, is a white, crystalline compound, slightly soluble in water, with a molecular weight of 244.3. It is designated chemically as (–)-L-α-hydrazino-α-methyl-β-(3,4-dihydroxybenzene) propanoic acid monohydrate.

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) 3Likely indication confounding 5Reporting / coding artifact 5Not in label — unassessed 26

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). 1,170 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Deep brain stimulation	192	220.0 185.0–261.6ROR 220.9 · calibrated p 2e-10 ✓	144.7 EB05 128.3 · IC025 +6.5 3/3 methods agree	Not in label — unassessed	serious n=187 · 88% consumer	not reported in cached trials
Freezing phenomenon	922	153.6 142.5–165.4ROR 156.6 · calibrated p 3e-9 ✓	113.7 EB05 107.6 · IC025 +6.6 3/3 methods agree	Not in label — unassessed	serious n=544 · 72% consumer	not reported in cached trials
Stoma site irritation	135	145.9 120.1–177.2ROR 146.3 · calibrated p 8e-9 ✓	108.0 EB05 93.6 · IC025 +6.0 3/3 methods agree	Not in label — unassessed	serious n=105 · 75% consumer	not reported in cached trials
Stoma site infection	297	132.8 116.7–151.1ROR 133.6 · calibrated p 1e-8 ✓	101.5 EB05 92.1 · IC025 +6.3 3/3 methods agree	Not in label — unassessed	serious n=212 · 73% consumer	not reported in cached trials
Stoma site discharge	613	128.2 117.2–140.2ROR 129.9 · calibrated p 2e-8 ✓	99.1 EB05 92.7 · IC025 +6.4 3/3 methods agree	Not in label — unassessed	serious n=413 · 72% consumer	not reported in cached trials
Stoma site erythema	406	123.4 110.6–137.7ROR 124.5 · calibrated p 2e-8 ✓	96.1 EB05 88.5 · IC025 +6.3 3/3 methods agree	Not in label — unassessed	serious n=295 · 72% consumer	not reported in cached trials
Labelled drug-food interaction medication error	105	117.2 94.5–145.4ROR 117.5 · calibrated p 5e-8 ✓	91.2 EB05 77.5 · IC025 +5.7 3/3 methods agree	Labeled (related wording) related wording	100% consumer	not reported in cached trials
Stoma site hypergranulation	128	113.0 93.0–137.2ROR 113.3 · calibrated p 6e-8 ✓	88.8 EB05 76.6 · IC025 +5.8 3/3 methods agree	Not in label — unassessed	serious n=99 · 72% consumer	not reported in cached trials
On and off phenomenon	1,053	111.2 104.0–118.9ROR 113.7 · calibrated p 4e-8 ✓	88.7 EB05 84.3 · IC025 +6.3 3/3 methods agree	Labeled (related wording) related wording	serious n=748	not reported in cached trials
Stoma site pain	290	110.0 96.7–125.1ROR 110.7 · calibrated p 6e-8 ✓	87.6 EB05 79.5 · IC025 +6.1 3/3 methods agree	Not in label — unassessed	serious n=207 · 71% consumer	not reported in cached trials
Stoma site odour	42	102.1 73.0–142.9ROR 102.2 · calibrated p 2e-7 ✓	80.1 EB05 61.7 · IC025 +4.9 3/3 methods agree	Not in label — unassessed	serious n=34 · 74% consumer	not reported in cached trials
Stoma site discomfort	38	91.4 64.4–129.6ROR 91.5 · calibrated p 5e-7 ✓	73.1 EB05 55.6 · IC025 +4.7 3/3 methods agree	Not in label — unassessed	serious n=26 · ♀ 68% (drug 43%)	not reported in cached trials
Stoma site induration	20	89.3 55.2–144.5ROR 89.4 · calibrated p 1e-6 ✓	69.6 EB05 47.6 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	–	not reported in cached trials
Dopamine dysregulation syndrome	74	88.0 68.6–113.0ROR 88.2 · calibrated p 4e-7 ✓	72.1 EB05 59.4 · IC025 +5.2 3/3 methods agree	Not in label — unassessed	serious n=68	not reported in cached trials
Stoma site reaction	112	88.0 71.9–107.8ROR 88.2 · calibrated p 4e-7 ✓	72.6 EB05 62.0 · IC025 +5.5 3/3 methods agree	Not in label — unassessed	serious n=92 · 74% consumer	not reported in cached trials
Stoma site extravasation	61	82.2 62.5–108.0ROR 82.3 · calibrated p 7e-7 ✓	67.9 EB05 54.8 · IC025 +5.1 3/3 methods agree	Not in label — unassessed	serious n=47	not reported in cached trials
Medical device battery replacement	19	77.0 47.3–125.4ROR 77.0 · calibrated p 3e-6 ✓	61.8 EB05 41.8 · IC025 +3.9 3/3 methods agree	Not in label — unassessed	serious n=18	not reported in cached trials
Catheter site nodule	23	75.7 48.6–117.8ROR 75.7 · calibrated p 3e-6 ✓	61.5 EB05 43.2 · IC025 +4.1 3/3 methods agree	Not in label — unassessed	serious n=20 · 100% consumer	not reported in cached trials
Device colour issue	58	75.3 57.0–99.5ROR 75.4 · calibrated p 1e-6 ✓	63.1 EB05 50.6 · IC025 +4.9 3/3 methods agree	Reporting / coding artifact	serious n=31 · 100% consumer	not reported in cached trials
Parkinsonism hyperpyrexia syndrome	26	74.4 49.1–112.7ROR 74.4 · calibrated p 3e-6 ✓	61.0 EB05 43.8 · IC025 +4.2 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious n=26 · 100% clinician	not reported in cached trials
Benign neoplasm of adrenal gland	21	72.4 45.6–114.8ROR 72.4 · calibrated p 4e-6 ✓	59.1 EB05 40.8 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious n=21 · ♀ 100% (drug 43%)	not reported in cached trials
Pathological gambling	223	67.9 59.0–78.1ROR 68.2 · calibrated p 2e-6 ✓	58.6 EB05 52.4 · IC025 +5.5 3/3 methods agree	Labeled adverse reaction exact term	serious n=117	not reported in cached trials
Medical device change	67	63.6 49.2–82.2ROR 63.7 · calibrated p 4e-6 ✓	54.8 EB05 44.7 · IC025 +4.9 3/3 methods agree	Not in label — unassessed	serious n=58 · 78% consumer	not reported in cached trials
Saliva discolouration	41	63.0 45.4–87.3ROR 63.0 · calibrated p 5e-6 ✓	53.9 EB05 41.4 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	78% consumer	not reported in cached trials
Stoma site oedema	27	62.2 41.6–93.1ROR 62.2 · calibrated p 7e-6 ✓	52.7 EB05 38.0 · IC025 +4.1 3/3 methods agree	Not in label — unassessed	serious n=23 · 100% consumer	not reported in cached trials
Stoma site haemorrhage	182	60.3 51.7–70.4ROR 60.6 · calibrated p 4e-6 ✓	52.9 EB05 46.7 · IC025 +5.3 3/3 methods agree	Not in label — unassessed	serious n=133 · 83% consumer	not reported in cached trials
Jealous delusion	33	58.2 40.5–83.7ROR 58.3 · calibrated p 1e-5 ✓	50.1 EB05 37.3 · IC025 +4.3 3/3 methods agree	Not in label — unassessed	serious n=30 · ♀ 0% (drug 43%) · 100% clinician	not reported in cached trials
Parkinson's disease	297	57.8 51.3–65.2ROR 58.2 · calibrated p 5e-6 ✓	51.0 EB05 46.3 · IC025 +5.4 3/3 methods agree	Likely indication confounding term in indications	serious n=263	NCT00099268: 1/371 (0.3%) on Carbidopa and Levodopa (serious AE)
Drug effect variable	128	55.7 46.4–67.0ROR 55.9 · calibrated p 8e-6 ✓	49.2 EB05 42.5 · IC025 +5.1 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious n=21 · 89% consumer	not reported in cached trials
Stoma complication	107	52.0 42.6–63.6ROR 52.2 · calibrated p 1e-5 ✓	46.3 EB05 39.4 · IC025 +4.9 3/3 methods agree	Reporting / coding artifact	serious n=76 · 84% consumer	not reported in cached trials
Device alarm issue	186	51.1 43.9–59.4ROR 51.3 · calibrated p 1e-5 ✓	45.6 EB05 40.4 · IC025 +5.1 3/3 methods agree	Reporting / coding artifact	serious n=112 · 86% consumer	not reported in cached trials
Reduced facial expression	100	49.2 40.0–60.5ROR 49.3 · calibrated p 2e-5 ✓	44.0 EB05 37.2 · IC025 +4.9 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious n=92	not reported in cached trials
Vitamin b6 deficiency	22	46.3 29.8–71.8ROR 46.3 · calibrated p 5e-5 ✓	40.6 EB05 28.3 · IC025 +3.7 3/3 methods agree	Likely indication confounding shares a disease stem with the indications wording	serious n=21	not reported in cached trials
Rapid eye movement sleep behaviour disorder	37	45.4 32.3–63.6ROR 45.4 · calibrated p 4e-5 ✓	40.4 EB05 30.6 · IC025 +4.2 3/3 methods agree	Not in label — unassessed	serious n=29	not reported in cached trials
Living in residential institution	171	44.4 37.9–51.9ROR 44.5 · calibrated p 3e-5 ✓	40.2 EB05 35.4 · IC025 +4.9 3/3 methods agree	Reporting / coding artifact	serious n=158 · 73% consumer	not reported in cached trials
Intentional medical device removal by patient	87	42.8 34.4–53.4ROR 42.9 · calibrated p 4e-5 ✓	38.8 EB05 32.4 · IC025 +4.6 3/3 methods agree	Labeled (related wording) related wording	serious n=81 · 83% consumer	not reported in cached trials
Multiple system atrophy	31	42.8 29.6–61.9ROR 42.8 · calibrated p 6e-5 ✓	38.2 EB05 28.2 · IC025 +4.0 3/3 methods agree	Not in label — unassessed	serious n=30	not reported in cached trials
Stoma site inflammation	65	42.5 33.0–54.9ROR 42.6 · calibrated p 5e-5 ✓	38.4 EB05 31.2 · IC025 +4.5 3/3 methods agree	Not in label — unassessed	serious n=56	not reported in cached trials
Bradykinesia	451	37.2 33.8–41.0ROR 37.6 · calibrated p 8e-5 ✓	34.3 EB05 31.8 · IC025 +4.9 3/3 methods agree	Not in label — unassessed	serious n=370	not reported in cached trials
Device programming error	24	36.6 24.1–55.5ROR 36.6 · calibrated p 2e-4 ✓	33.1 EB05 23.4 · IC025 +3.7 3/3 methods agree	Reporting / coding artifact	100% consumer	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 Carbidopa and Levodopa 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 (1 of 40 signal terms matched).

NCT00099268 — Efficacy and Safety of Carbidopa/Levodopa/Entacapone in Patients With Parkinson's Disease Requiring Initiation (N=747, PHASE3; 225 AE terms posted; arms: Carbidopa/Levodopa/Entacapone; Carbidopa/Levodopa)

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	4,472	6.0 5.9–6.2ROR 6.6 · calibrated p 0.117	6.0 EB05 5.8 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.8 · 72% consumer	NCT00099268: 7/371 (1.9%) on Carbidopa and Levodopa (serious AE)
Drug ineffective (drug did not work)	4,091	1.4 1.3–1.4ROR 1.4 · calibrated p 0.588	1.4 EB05 1.3 · IC025 +0.4	Reporting / coding artifact	serious PRR 1.3 · 73% consumer	not reported in cached trials
Hallucination (hallucinations)	3,937	24.6 23.9–25.4ROR 26.8 · calibrated p 5e-4 ✓	23.3 EB05 22.7 · IC025 +4.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 19.6	NCT00099268: 1/373 (0.3%) on Carbidopa and Levodopa (serious AE)
Tremor (shaking)	3,312	9.0 8.7–9.3ROR 9.6 · calibrated p 0.037 ✓	8.9 EB05 8.6 · IC025 +3.1 3/3 methods agree	Not in label — unassessed	serious PRR 5.7 · 79% consumer	NCT00099268: 1/373 (0.3%) on Carbidopa and Levodopa (serious AE)
Dyskinesia (involuntary movements)	3,021	35.7 34.5–37.0ROR 38.1 · calibrated p 7e-5 ✓	33.1 EB05 32.1 · IC025 +5.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 22.7 · 71% consumer	NCT00099268: 10/371 (2.7%) on Carbidopa and Levodopa
Death	2,905	1.5 1.4–1.6ROR 1.5 · calibrated p 0.664	1.5 EB05 1.5 · IC025 +0.5	Outcome field, not a reaction	serious PRR 1.6	not reported in cached trials
Dizziness	2,521	2.3 2.2–2.3ROR 2.3 · calibrated p 0.890	2.3 EB05 2.2 · IC025 +1.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 1.7 · 71% consumer	NCT00099268: 46/371 (12.4%) on Carbidopa and Levodopa
Nausea	2,382	1.3 1.3–1.4ROR 1.4 · calibrated p 0.550	1.3 EB05 1.3 · IC025 +0.4	Likely indication confounding term in indications; also in warnings	serious PRR 1.0 · 72% consumer	NCT00099268: 3/371 (0.8%) on Carbidopa and Levodopa (serious AE)
Confusional state (confusion)	2,160	6.0 5.8–6.3ROR 6.2 · calibrated p 0.135	5.9 EB05 5.7 · IC025 +2.5 3/3 methods agree	Labeled (related wording) related wording	serious PRR 5.1	not reported in cached trials
Gait disturbance	2,030	4.7 4.5–4.9ROR 4.9 · calibrated p 0.244	4.7 EB05 4.5 · IC025 +2.2 3/3 methods agree	Not in label — unassessed	serious PRR 4.3	not reported in cached trials
Fatigue (tiredness)	2,009	1.2 1.1–1.2ROR 1.2 · calibrated p 0.411	1.1 EB05 1.1 · IC025 +0.1	Labeled adverse reaction exact term	serious PRR 1.1 · 71% consumer	NCT00099268: 42/371 (11.3%) on Carbidopa and Levodopa
Somnolence (drowsiness)	2,007	4.5 4.3–4.7ROR 4.6 · calibrated p 0.279	4.4 EB05 4.3 · IC025 +2.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 3.5 · 71% consumer	NCT00099268: 28/371 (7.5%) on Carbidopa and Levodopa
Asthenia (weakness)	1,844	2.2 2.1–2.3ROR 2.2 · calibrated p 0.935	2.2 EB05 2.1 · IC025 +1.0 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 2.0 · 70% consumer	not reported in cached trials
Urinary tract infection (bladder infection)	1,497	3.9 3.7–4.1ROR 4.0 · calibrated p 0.371	3.9 EB05 3.7 · IC025 +1.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 4.6 · 73% consumer	NCT00099268: 1/373 (0.3%) on Carbidopa and Levodopa (serious AE)
Anxiety	1,418	2.2 2.1–2.3ROR 2.3 · calibrated p 0.925	2.2 EB05 2.1 · IC025 +1.1 3/3 methods agree	Not in label — unassessed	serious PRR 1.9 · 71% consumer	NCT00099268: 27/371 (7.3%) on Carbidopa and Levodopa

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.

Deep brain stimulation — n=192, PRR 220.0
Freezing phenomenon — n=922, PRR 153.6
Stoma site irritation — n=135, PRR 145.9
Stoma site infection — n=297, PRR 132.8
Stoma site discharge — n=613, PRR 128.2
Stoma site erythema — n=406, PRR 123.4
Stoma site hypergranulation — n=128, PRR 113.0
Stoma site pain — n=290, PRR 110.0
Stoma site odour — n=42, PRR 102.1
Stoma site discomfort — n=38, PRR 91.4

✓ A hand-written Bradford Hill causality assessment exists for this drug: Levodopa ↔ 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 Carbidopa and Levodopa?

In FDA FAERS, the most frequently co-reported reaction terms for Carbidopa and Levodopa are fall, hallucination, tremor, dyskinesia, dizziness, 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 Carbidopa and Levodopa have an FDA boxed warning?

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

Do FAERS signals prove that Carbidopa and Levodopa 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 55b99f22-9eb2-4df6-9979-bc4c3af5e454, effective 20251217; matched on openfda.generic_name.exact:"CARBIDOPA")
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, field patient.drug.openfda.generic_name.exact, 1,210 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 CARBIDOPA, 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.