Venlafaxine vs Fluoxetine: side effects in FDA adverse event reports
At a glance
| Venlafaxine | Fluoxetine | |
|---|---|---|
| Drug class | – | – |
| Brand names | – | – |
| FAERS reports | 131,548 | 126,801 |
| Serious | 74% | 72% |
| Death outcome | 13,161 | 12,911 |
| Boxed warning | Yes WARNING: SUICIDALITY AND ANTIDEPRESSANT DRUGS Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children | Yes SUICIDAL THOUGHTS AND BEHAVIORS • Antidepressants increased the risk of suicidal thoughts and behavior in children, adolescents, and young adults in short-term |
Signals both drugs share
| Reaction | Venlafaxine | Fluoxetine | Label screen (A / B) |
|---|---|---|---|
| Serotonin syndrome | 2,520 · PRR 24.1 | 2,364 · PRR 23.2 | Labeled — boxed warning / Labeled — boxed warning |
| Major depression | 745 · PRR 18.0 | 584 · PRR 14.2 | Labeled (related wording) / Likely indication confounding |
| Hyperreflexia | 245 · PRR 11.9 | 212 · PRR 10.6 | Labeled adverse reaction / Labeled adverse reaction |
| Anorgasmia | 158 · PRR 9.8 | 178 · PRR 11.5 | Labeled adverse reaction / Labeled adverse reaction |
| Clonus | 164 · PRR 10.1 | 163 · PRR 10.4 | Labeled adverse reaction / Labeled adverse reaction |
| Hostility | 154 · PRR 10.1 | 122 · PRR 8.2 | Labeled adverse reaction / Labeled adverse reaction |
| Atrial septal defect | 419 · PRR 8.3 | 412 · PRR 8.5 | Not in label — unassessed / Not in label — unassessed |
| Physical deconditioning | 298 · PRR 21.4 | 292 · PRR 21.7 | Not in label — unassessed / Not in label — unassessed |
| Urinary tract disorder | 245 · PRR 9.1 | 233 · PRR 9.0 | Not in label — unassessed / Not in label — unassessed |
| Amaurosis fugax | 222 · PRR 41.6 | 229 · PRR 44.9 | Not in label — unassessed / Not in label — unassessed |
| Tearfulness | 217 · PRR 8.4 | 228 · PRR 9.2 | Not in label — unassessed / Not in label — unassessed |
| Reversible cerebral vasoconstriction syndrome | 118 · PRR 10.1 | 162 · PRR 14.8 | Not in label — unassessed / Not in label — unassessed |
| Derealisation | 134 · PRR 10.6 | 107 · PRR 8.7 | Not in label — unassessed / Not in label — unassessed |
| Bezoar | 113 · PRR 14.2 | 115 · PRR 15.0 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Venlafaxine
- Suicide attempt — n=3,232, PRR 8.9 Labeled — boxed warning
- Withdrawal syndrome — n=2,166, PRR 8.6 Labeled adverse reaction
- Mydriasis — n=682, PRR 8.9 Labeled adverse reaction
- Electric shock sensation — n=251, PRR 16.3 Labeled adverse reaction
- Homicidal ideation — n=235, PRR 9.7 Labeled adverse reaction
- Hypomania — n=196, PRR 8.9 Labeled — boxed warning
- Selective eating disorder — n=127, PRR 25.7 Labeled (related wording)
- Sleep paralysis — n=94, PRR 10.9 Labeled (related wording)
Labeled signals distinctive to Fluoxetine
- Akathisia — n=682, PRR 8.6 Labeled adverse reaction
- Torsade de pointes — n=372, PRR 8.2 Labeled (related wording)
- Flat affect — n=138, PRR 10.6 Labeled (related wording)
- Congenital cardiovascular anomaly — n=97, PRR 21.2 Labeled (related wording)
Common questions
Which has more reported side effects, Venlafaxine or Fluoxetine?
Venlafaxine has 131,548 FAERS reports and Fluoxetine 126,801. More reports does not mean more dangerous: volume follows how widely and how long a drug has been used, prescription vs over-the-counter status, and publicity. The seriousness share (74% vs 72%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Venlafaxine and Fluoxetine share?
Both drugs carry disproportionality signals for serotonin syndrome, major depression, hyperreflexia, anorgasmia, clonus. Shared signals often reflect a shared drug class or the condition both are used for.
Is Venlafaxine or Fluoxetine safer?
FAERS cannot answer that: it has no denominator and no comparator. Use this page to see which risks are already on each label and which signals are unlabeled, then check the prescribing information and your clinician for your situation.
Sources: openFDA FAERS pair statistics (OpenPV build 2026-09-14), FDA labels via openFDA, openFDA count queries for seriousness and deaths. Pair chosen because it is a commonly searched comparison. Generated 2026-10-08.