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Entacapone Side Effects

The most commonly reported side effects of entacapone include fall, hallucination, and parkinson^s disease, based on 14,437 FDA adverse event reports from 2004 to 2025. 4.7% of reports found the drug to be ineffective.

Entacapone side effects

Percentages show how often each reaction appears relative to total reports for entacapone.

1
Fall8.3%1,192
2
Hallucination7.4%1,062
3
Parkinson^s Disease7.2%1,036
4
Dyskinesia7.0%1,014
5
Death5.6%811
6
Drug Ineffective4.7%681
7
Confusional State4.3%617
8
Gait Disturbance4.1%594
9
Tremor4.0%573
10
Dysphagia3.2%464
11
On And Off Phenomenon3.1%448
12
Somnolence3.1%446
13
Asthenia2.9%422
14
Nausea2.9%421
15
Dizziness2.8%410

These are voluntary reports and do not establish that entacapone caused these reactions.

Report severity

81.6%Serious11,782 reports
39.1%Hospitalizations5,646 reports
15.5%Fatal2,244 reports

Seriousness is determined by the reporter, not by OpenClaim.

Entacapone drug interactions

Other drugs that appear in adverse event reports alongside entacapone. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Levodopa47.5%6,864
2
Carbidopa44.3%6,391
3
Pimavanserin8.5%1,232
4
Ropinirole-hydrochloride5.2%749
5
Apomorphine-hydrochloride4.5%653
6
Pramipexole-dihydrochloride4.4%640
7
Amantadine4.0%576
8
Rasagiline-mesylate3.8%550
9
Rotigotine3.6%519
10
Istradefylline2.2%317
11
Quetiapine-fumarate1.8%253
12
Clozapine1.7%245
13
Rivastigmine1.6%235
14
Droxidopa1.1%164
15
Selegiline1.1%154

Taken alongside

1
Levodopa48.9%7,055
2
Carbidopa47.0%6,787
3
Amantadine10.4%1,498
4
Aspirin10.3%1,482
5
Pramipexole-dihydrochloride10.3%1,481
6
Rasagiline-mesylate8.8%1,265
7
Ropinirole-hydrochloride8.7%1,255
8
Quetiapine-fumarate7.1%1,030
9
Ergocalciferol6.8%983
10
Acetaminophen6.6%956
11
Clonazepam6.6%946
12
Atorvastatin-calcium6.1%880
13
Levothyroxine-sodium5.7%818
14
Omeprazole5.5%793
15
Gabapentin5.0%717

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports entacapone side effects

37.6% of entacapone adverse event reports involve female patients and 56.4% involve male patients. The largest age group is elderly at 77%. These figures reflect who reports side effects, not underlying risk.

Sex

Female37.6%
Male56.4%
Unknown6.1%

Age group

< 2<0.1%
2–11<0.1%
12–17<0.1%
18–6422.3%
65+77.5%

What is entacapone used for

Conditions and purposes for which patients were taking entacapone when the adverse event was reported.

AbasiaAbnormal BehaviourAdjuvant TherapyAdverse EventAgitationAkinesiaAlzheimer^s DiseaseAnaemiaAnorexiaArteriosclerosisArthritisAstheniaAbdominal PainBalance DisorderBasal Ganglion Degeneration

Showing 15 of 140 indications

Entacapone brand names and reporting trend

Entacapone is sold under the brand name Comtan.

Brand names

Comtan4,772

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking entacapone with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.