Catechol-O-Methyltransferase Inhibitor side effects compared: 3 drugs, 6,764 FDA adverse event reports
Members
| Drug | FAERS reports | Serious | Death outcome | Boxed warning | Top labeled signals | Unlabeled (unassessed) |
|---|---|---|---|---|---|---|
| Entacapone | 4,154 | 71% | 639 | – | Dyskinesia; Agitation; Hypokinesia | Hallucination; Confusional state |
| Opicapone (Ongentys) | 2,261 | 75% | 235 | – | Hallucination; Dyskinesia; Hallucination, visual | Tremor; Mobility decreased |
| Tolcapone | 349 | 88% | 62 | boxed | Dyskinesia | – |
Class-wide signals (flagged in at least 2 of 3 members)
| Reaction | Members flagged | Median PRR | Reports (sum) | In label |
|---|---|---|---|---|
| Dyskinesia | 3/3 | 60.6 | 813 | 3/3 members' labels |
| Muscle rigidity | 2/3 | 63.0 | 230 | 0/2 members' labels |
| Hallucination, visual | 2/3 | 44.4 | 287 | 1/2 members' labels |
| Delusion | 2/3 | 38.2 | 177 | 1/2 members' labels |
| Dystonia | 2/3 | 36.4 | 208 | 0/2 members' labels |
| Hallucination | 2/3 | 36.3 | 810 | 1/2 members' labels |
| Hypokinesia | 2/3 | 31.4 | 114 | 1/2 members' labels |
| Orthostatic hypotension | 2/3 | 24.4 | 131 | 1/2 members' labels |
| Psychotic disorder | 2/3 | 16.0 | 146 | 1/2 members' labels |
| Joint dislocation | 2/3 | 16.0 | 48 | 0/2 members' labels |
| Delirium | 2/3 | 14.0 | 138 | 0/2 members' labels |
| Dementia | 2/3 | 13.8 | 115 | 0/2 members' labels |
| Paranoia | 2/3 | 13.0 | 72 | 0/2 members' labels |
| Motor dysfunction | 2/3 | 11.8 | 37 | 0/2 members' labels |
| Initial insomnia | 2/3 | 11.0 | 36 | 0/2 members' labels |
| Mobility decreased | 2/3 | 10.4 | 217 | 0/2 members' labels |
| Cognitive disorder | 2/3 | 9.7 | 145 | 0/2 members' labels |
| Mania | 2/3 | 9.6 | 50 | 0/2 members' labels |
| Aggression | 2/3 | 9.6 | 147 | 1/2 members' labels |
| Gait inability | 2/3 | 9.3 | 93 | 0/2 members' labels |
| Speech disorder | 2/3 | 8.9 | 141 | 0/2 members' labels |
| Restlessness | 2/3 | 8.7 | 100 | 0/2 members' labels |
| Balance disorder | 2/3 | 8.7 | 233 | 0/2 members' labels |
Member-specific signals (flagged in exactly one drug)
No strong single-member signals (n ≥ 50) in this class.
Common questions
Which catechol-o-methyltransferase inhibitor has the most FDA adverse event reports?
Entacapone has the most FAERS co-reports in this class (4,154), followed by Opicapone (2,261). Report volume tracks how widely and how long a drug has been used, and how much attention it has had, far more than its risk.
Which side effects are shared across catechol-o-methyltransferase inhibitor drugs?
Reaction terms flagged in at least half of the 3 members include dyskinesia, muscle rigidity, hallucination, visual, delusion, dystonia. A term shared across a class usually reflects the shared mechanism (or the shared patient population) rather than one product.
Does a FAERS signal mean the drug causes the reaction?
No. These are disproportionality signals from voluntary reports with no denominator. Each is screened against the FDA label (known vs unlabeled) on the drug pages; causality needs temporality, dose-response, plausibility and trial or cohort evidence.
Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, seriousness and death counts from openFDA count queries. Generated 2026-10-08. Not medical advice.