Encephalopathy adverse event reports that record this term
- Kind of term
- MedDRA preferred term
What a report is
A report is not proof that the drug was the cause of the event.
FDA says:
Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on . The data have the reports that FDA received through .
FDA also says:
There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event. The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.
Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on .
Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.
Reports on file
From January 2004 to June 2026, FDA received 24,091 adverse event reports that record the MedDRA preferred term Encephalopathy. The person who codes a report selects the term that agrees best with the description of the reporter.
FDA received 1,655 reports in the 12 months to June 2026 and 1,386 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.
By reports in the 12 months to June 2026, this term was number 414 of 1,436 reaction terms with a page. Of the 1,332,454 drug reports that FDA received in the 12 months to June 2026, 1,655 (0.1%) record this term. Reports for male patients were 43.1% of the reports that record this term and 34.6% of all drug reports.
The number of people who use the product is not in the data. A count is not a rate.
MedDRA
The Medical Dictionary for Regulatory Activities. The person who codes a report selects the preferred term that agrees best with the description of the reporter. FDA does not publish the description.
Data version
openFDA FAERS release of 29 Oct 2026. Reports received through 30 Jun 2026.
Drugs in these reports
The table has the 94 drug pages with 100 or more reports that record this term. The rows are in order of name. A drug page with fewer reports for this term is not in the table. The counts are the counts that the site keeps for each reaction term, and a count can be lower than the count of FDA.
FDA says:
Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .
| Drug | Class | Reports with this term |
|---|---|---|
| Acetaminophen | 584 | |
| Acyclovir | Herpes simplex virus nucleoside analog DNA polymerase inhibitor | 247 |
| Alprazolam | Benzodiazepine | 159 |
| Amlodipine | Calcium channel blocker | 115 |
| Amoxicillin | Penicillin-class antibacterial | 112 |
| Aspirin | Nonsteroidal anti-inflammatory drug | 136 |
| Atezolizumab | Programmed death Receptor-1 blocking antibody | 129 |
| Baclofen | gamma-Aminobutyric acid-ergic agonist | 911 |
| Bactrim | Dihydrofolate reductase inhibitor antibacterial | 128 |
| Bevacizumab | Vascular endothelial growth factor inhibitor | 200 |
| Bupropion | Aminoketone | 169 |
| Carbamazepine | Mood stabilizer | 128 |
| Carboplatin | Platinum-based drug | 321 |
| Cefepime | Cephalosporin antibacterial | 361 |
| Ceftriaxone | Cephalosporin antibacterial | 120 |
| Ciprofloxacin | Fluoroquinolone antibacterial | 111 |
| Cisplatin | Platinum-based drug | 202 |
| Clobazam | Benzodiazepine | 177 |
| Clonazepam | Benzodiazepine | 260 |
| Clozapine | Atypical antipsychotic | 164 |
| Cyclophosphamide | Alkylating drug | 626 |
| Cyclosporine | Calcineurin inhibitor immunosuppressant | 166 |
| Cytarabine | Nucleoside metabolic inhibitor | 396 |
| Dexamethasone | Corticosteroid | 483 |
| Diazepam | Benzodiazepine | 242 |
| Doxorubicin | Anthracycline topoisomerase inhibitor | 168 |
| Doxorubicin hydrochloride | Anthracycline topoisomerase inhibitor | 160 |
| Emend | Substance P/Neurokinin-1 receptor antagonist | 134 |
| Etoposide | Topoisomerase inhibitor | 408 |
| Fentanyl | Opioid agonist | 211 |
| Fludarabine | Nucleoside metabolic inhibitor | 190 |
| Fluorouracil | Nucleoside metabolic inhibitor | 255 |
| Furosemide | Loop diuretic | 204 |
| Gabapentin | Anti-epileptic agent | 332 |
| Haloperidol | Typical antipsychotic | 104 |
| Holoxan | 110 | |
| Ibuprofen | Nonsteroidal anti-inflammatory drug | 138 |
| Ifosfamide | Alkylating drug | 611 |
| Ipilimumab | CTLA-4-directed blocking antibody | 122 |
| Isoniazid | Antimycobacterial | 125 |
| Keppra | 141 | |
| Keytruda | Programmed death Receptor-1 blocking antibody | 121 |
| Lamotrigine | Anti-epileptic agent | 282 |
| Levetiracetam | 397 | |
| Levofloxacin | Fluoroquinolone antibacterial | 139 |
| Lithium | Mood stabilizer | 157 |
| Lorazepam | Benzodiazepine | 178 |
| Lyrica | 105 | |
| Meropenem | Penem antibacterial | 149 |
| Mesna | Cytoprotective agent | 144 |
| Metformin | Biguanide | 288 |
| Metformin hydrochloride | Biguanide | 125 |
| Methadone | Opioid agonist | 103 |
| Methotrexate | Folate analog metabolic inhibitor | 890 |
| Methotrexate sodium | Folate analog metabolic inhibitor | 130 |
| Methylprednisolone | Corticosteroid | 330 |
| Metronidazole | Nitroimidazole antimicrobial | 416 |
| Mirtazapine | 123 | |
| Morphine | Opioid agonist | 144 |
| Mycophenolate mofetil | Antimetabolite immunosuppressant | 365 |
| Nexavar | Kinase inhibitor | 124 |
| Nivolumab | Programmed death Receptor-1 blocking antibody | 228 |
| Olanzapine | Atypical antipsychotic | 140 |
| Omeprazole | Proton pump inhibitor | 125 |
| Oxaliplatin | Platinum-based drug | 206 |
| Oxycodone | Opioid agonist | 106 |
| Paclitaxel | Microtubule inhibitor | 135 |
| Pantoprazole | Proton pump inhibitor | 113 |
| Paracetamol | 241 | |
| Paroxetine | Serotonin reuptake inhibitor | 141 |
| Phenytoin | Anti-epileptic agent | 146 |
| Prednisolone | Corticosteroid | 220 |
| Prednisone | Corticosteroid | 630 |
| Pregabalin | 154 | |
| Prograf | Calcineurin inhibitor immunosuppressant | 110 |
| Propofol | General anesthetic | 121 |
| Quetiapine | Atypical antipsychotic | 253 |
| Revlimid | Thalidomide analog | 146 |
| Ribavirin | Nucleoside analog antiviral | 245 |
| Risperidone | Atypical antipsychotic | 151 |
| Rituximab | CD20-directed cytolytic antibody | 371 |
| Tacrolimus | Calcineurin inhibitor immunosuppressant | 647 |
| Topiramate | 176 | |
| Tramadol | 203 | |
| Trazodone | 151 | |
| Valproate sodium | Anti-epileptic agent | 163 |
| Valproic acid | Anti-epileptic agent | 290 |
| Valtrex | Herpes simplex virus nucleoside analog DNA polymerase inhibitor | 225 |
| Vancomycin | Glycopeptide antibacterial | 196 |
| Venlafaxine | Serotonin and norepinephrine reuptake inhibitor | 204 |
| Vincristine | 265 | |
| Vincristine sulfate | Vinca alkaloid | 179 |
| Yescarta | CD19-directed chimeric antigen receptor | 243 |
| Zolpidem | gamma-Aminobutyric acid A receptor positive modulator | 120 |
The page of each drug has the count of each reaction term in its reaction lookup.
Drug classes in these reports
The table has the 35 pharmacologic classes with 250 or more reports that record this term. The rows are in order of name.
FDA says:
Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of . The site read the page on .
A class with many reports in all has many reports for almost every term.
Reports by month
FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.
Patients in these reports
| Age | Reports | Share | Share as a bar |
|---|---|---|---|
| Under 2 | 305 | 1.3% | |
| 2 to 11 | 991 | 4.1% | |
| 12 to 17 | 855 | 3.5% | |
| 18 to 44 | 3,548 | 14.7% | |
| 45 to 64 | 6,028 | 25% | |
| 65 to 74 | 3,961 | 16.4% | |
| 75 and over | 3,271 | 13.6% | |
| Age not given | 5,132 | 21.3% |
| Sex | Reports | Share | Share as a bar |
|---|---|---|---|
| Female | 10,784 | 44.8% | |
| Male | 10,372 | 43.1% | |
| Unknown or not given | 2,935 | 12.2% |
Age and sex are as the report gives them. 46.5% of these reports give the United States as the country.
Terms near this one
- Emotional disorder
- Emotional distress
- Emphysema
- Encephalitis
- End stage renal disease
- Endocarditis
- Endophthalmitis
- Energy increased
These are the next terms in the A to Z list. The links are for navigation.
Official pages
- MedWatch Online Voluntary Reporting FormThe online form of FDA for a voluntary report.
- MedWatch: The FDA Safety Information and Adverse Event Reporting ProgramThe page of the FDA program that receives reports about drugs and devices.
- FDA Adverse Event Monitoring System (AEMS) Public DashboardThe public dashboard of FDA for adverse event reports on drugs and biologics.
The site checked these addresses on . The links open in a new tab.
Cite this page
Reported Reactions. Encephalopathy: adverse event reports that record this term. https://reportedreactions.com/reaction/encephalopathy/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of . Reports received through .
Where the data come from
The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 29 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Nov 2026. A class is the pharmacologic class (EPC) of the FDA label.
The count has the reports with each spelling of one MedDRA preferred term. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.
Questions
What does Encephalopathy mean in an adverse event report?
It is a MedDRA preferred term. FDA codes the description of a reporter with the MedDRA dictionary. The openFDA files do not have the description itself, and this site does not show it.
Does a drug in the table mean that the drug was responsible for this reaction?
No. FDA says:
No individual drug is connected to any individual reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on .
What does this page tell a person who has this symptom?
This page gives counts of reports. It cannot assess a person. A pharmacist or a clinician can assess a person.
If this is a medical emergency, please call 911.
Source: FDA, MedWatch Online Voluntary Reporting Form. The site read the page on .