What the label lists and what reports show
Tolcapone side effects
Tolcapone's FDA label lists its adverse reactions in its own words. FAERS holds 349 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 fall (30 reports).
- Generic listed
- Boxed warning
Check it at the source: the tolcapone FDA label on DailyMed (effective October 2, 2020, Bausch Health US LLC); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsCases of severe hepatocellular injury, including fulminant liver failure resulting in death, have been reported in postmarketing use. As of May 2005, three cases of fatal fulminant hepatic failure have been reported from more than 40,000 patient years of worldwide use. This incidence may be 10- to 100-fold higher than the background incidence in the general population. All three cases were reported within the first six months of initiation of treatment with TASMAR. Analysis of the laboratory monitoring data in over 3,400 TASMAR-treated patients participating in clinical trials indicated that increases in SGPT/ALT or SGOT/AST, when present, generally occurred within the first 6 months of treatment with TASMAR. The imprecision of the estimated increase is due to uncertainties about the base rate and the actual number of cases occurring in association with TASMAR. …
Table 4. Summary of Patients With Adverse Reactions After Start of Trial Drug Administration (At Least 1% in TASMAR Group and at Least One TASMAR Dose Group Greater Than Placebo)
| Adverse Reactions | N = 298 (%) | N = 296 (%) | N = 298 (%) |
|---|---|---|---|
| Dyskinesia | 20 | 42 | 51 |
| Nausea | 18 | 30 | 35 |
| Sleep Disorder | 18 | 24 | 25 |
| Dystonia | 17 | 19 | 22 |
| Dreaming Excessive | 17 | 21 | 16 |
| Anorexia | 13 | 19 | 23 |
| Cramps Muscle | 17 | 17 | 18 |
| Orthostatic Complaints | 14 | 17 | 17 |
| Somnolence | 13 | 18 | 14 |
| Diarrhea | 8 | 16 | 18 |
| Confusion | 9 | 11 | 10 |
| Dizziness | 10 | 13 | 6 |
| Headache | 7 | 10 | 11 |
| Hallucination | 5 | 8 | 10 |
| Vomiting | 4 | 8 | 10 |
| Constipation | 5 | 6 | 8 |
| Fatigue | 6 | 7 | 3 |
| Upper Respiratory Tract Infection | 3 | 5 | 7 |
| Falling | 4 | 4 | 6 |
| Sweating Increased | 2 | 4 | 7 |
| Urinary Tract Infection | 4 | 5 | 5 |
| Xerostomia | 2 | 5 | 6 |
| Abdominal Pain | 3 | 5 | 6 |
| Syncope | 3 | 4 | 5 |
| Urine Discoloration | 1 | 2 | 7 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
Source: FDA drug label, Bausch Health US LLC, effective October 2, 2020 (SPL set a0e47a9d-78e7-4523-983a-aa259f221736), via openFDA; the full label on DailyMed
What do FAERS reports show?
349 reports list tolcapone among the medicines taken, each a report of something that happened, not proof the medicine caused it; 62 are coded as a death and 170 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 21 reactions below, 9 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.
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?
- Tolcapone: 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