What the label lists and what reports show
Opicapone side effects
Opicapone's FDA label: “Most common adverse reactions (≥4% and > placebo): dyskinesia, constipation, blood creatine kinase increased, hypotension/syncope, and weight decreased.” FAERS holds 2,261 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is hallucination (314 reports).
- No generic listed
Check it at the source: the opicapone FDA label on DailyMed (effective October 15, 2025, Amneal Pharmaceuticals LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of ONGENTYS?ONGENTYS may cause serious side effects, including: Falling asleep during normal activities. You may suddenly fall asleep while doing normal activities such as driving a car, talking or eating while taking ONGENTYS or other medicines used to treat Parkinson’s disease, without being drowsy or without warning. This may result in having accidents. Your chances of falling asleep while doing normal activities while taking ONGENTYS are higher if you take other medicines that cause drowsiness. Low blood pressure or dizziness. Low blood pressure, dizziness, light headedness, or fainting can happen with ONGENTYS. Tell your healthcare provider if you become dizzy, lightheaded, or faint while taking ONGENTYS. Uncontrolled sudden movements (dyskinesia). ONGENTYS may cause uncontrolled sudden movements or make such movements you already have worse or happen more often. […]
Source: FDA drug label, Amneal Pharmaceuticals LLC, effective October 15, 2025 (SPL set a511a531-112e-43f8-a43f-5334b0efe979), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥4% and > placebo): dyskinesia, constipation, blood creatine kinase increased, hypotension/syncope, and weight decreased.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are discussed in more detail in other sections of the labeling: Cardiovascular Effects with Concomitant Use of Drugs Metabolized by Catechol-O-Methyltransferase (COMT) [see Warnings and Precautions ( 5.1 )] Falling Asleep During Activities of Daily Living and Somnolence [see Warnings and Precautions ( 5.2 )] Hypotension/Syncope [see Warnings and Precautions ( 5.3 )] Dyskinesia [see Warnings and Precautions ( 5.4 )] Hallucinations and Psychosis [see Warnings and Precautions ( 5.5 )] Impulse Control/Compulsive Disorders [see Warnings and Precautions ( 5.6 )] Withdrawal-Emergent Hyperpyrexia and Confusion [see Warnings and Precautions ( 5.7 )] Most common adverse reactions (≥4% and > placebo): dyskinesia, constipation, blood creatine kinase increased, hypotension/syncope, and weight decreased. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. …
Source: FDA drug label, Amneal Pharmaceuticals LLC, effective October 15, 2025 (SPL set a511a531-112e-43f8-a43f-5334b0efe979), via openFDA; the full label on DailyMed
What do FAERS reports show?
2,261 reports list opicapone among the medicines taken, each a report of something that happened, not proof the medicine caused it; 235 are coded as a death and 929 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 23 reactions below, 6 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Opicapone: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions