memantine Side Effects
Also known as: Namenda
Analysis of 12,807 adverse event reports submitted to the FDA from 2004 to 2025.
Total Reports
12,807
Death-Related
1,934
15.1% of reports
Hospitalizations
5,255
41.0% of reports
Top Indication
Product Used For Unknown Indication
Most Reported Adverse Reactions
Who Reports Side Effects
Gender Distribution
Age Distribution
Reporting Trend by Year
Reactions in Death Reports
Top reactions reported in 1,934 reports where death was an outcome. These are voluntarily reported and do not establish causation.
| Reaction | Reports |
|---|---|
| DEATH | 849 |
| PNEUMONIA | 118 |
| FALL | 107 |
| OFF LABEL USE | 80 |
| HALLUCINATION | 79 |
| PARKINSON^S DISEASE | 77 |
| CONDITION AGGRAVATED | 74 |
| CONFUSIONAL STATE | 72 |
| TOXICITY TO VARIOUS AGENTS | 68 |
| ASTHENIA | 67 |
| DEMENTIA | 67 |
| DRUG INEFFECTIVE | 66 |
| URINARY TRACT INFECTION | 64 |
| DYSPHAGIA | 63 |
| SEPSIS | 63 |
| COMPLETED SUICIDE | 54 |
| PNEUMONIA ASPIRATION | 50 |
| FATIGUE | 49 |
| DYSPNOEA | 48 |
| GENERAL PHYSICAL HEALTH DETERIORATION | 46 |
Reactions in Hospitalization Reports
Top reactions in 5,255 reports where hospitalization was an outcome.
| Reaction | Reports |
|---|---|
| FALL | 607 |
| CONFUSIONAL STATE | 330 |
| URINARY TRACT INFECTION | 299 |
| PNEUMONIA | 255 |
| ASTHENIA | 246 |
| FATIGUE | 243 |
| OFF LABEL USE | 234 |
| DRUG INEFFECTIVE | 225 |
| NAUSEA | 188 |
| DRUG INTERACTION | 187 |
| SOMNOLENCE | 180 |
| DEHYDRATION | 176 |
| VOMITING | 176 |
| DELIRIUM | 159 |
| CONDITION AGGRAVATED | 157 |
| HYPOTENSION | 157 |
| AGITATION | 156 |
| DIARRHOEA | 156 |
| DYSPNOEA | 154 |
| BRADYCARDIA | 153 |
Nearby — Related Medications
What the FAERS Data Reveals About memantine Side Effects
The FDA Adverse Event Reporting System (FAERS) contains 12,807 voluntary reports linked to memantine and its brand equivalents (Namenda), spanning 2004 through 2025. Of those, 1,934 (15.1%) listed death as an outcome and 5,255 (41.0%) involved hospitalization. The most common indication reported alongside adverse events was Product Used For Unknown Indication.
Demographic breakdowns help contextualize who is being exposed to the drug. Of reports with known sex, 52% were female and 48% male; age distribution skews toward 75+, with 5,631 reports in that bracket. The single most reported reaction is fall with 937 submissions, followed by death and drug ineffective.
FAERS is a signal-detection tool, not a scorecard. Reports are voluntary, and a single case may list multiple suspect drugs, so numbers above should not be read as incidence rates or per-patient risk. Widely prescribed drugs naturally accumulate more reports than niche therapies even when individual risk is low. These aggregates are useful for spotting patterns that merit further pharmacovigilance, not for choosing between medications. This page is for educational reference only and is not medical advice — speak with a licensed clinician about any side-effect concerns.
Read our methodology — how this data is sourced, computed, and verified.