Clonazepam vs Clozapine: side effects in FDA adverse event reports
At a glance
| Clonazepam | Clozapine | |
|---|---|---|
| Drug class | Benzodiazepine | Atypical Antipsychotic |
| Brand names | – | – |
| FAERS reports | 159,258 | 124,826 |
| Serious | 68% | 95% |
| Death outcome | 18,605 | 22,310 |
| Boxed warning | Yes RISKS FROM CONCOMITANT USE WITH OPIOIDS; ABUSE, MISUSE, AND ADDICTION; and DEPENDENCE AND WITHDRAWAL REACTIONS Concomitant use of benzodiazepines and opioids ma | Yes WARNING: SEVERE NEUTROPENIA; ORTHOSTATIC HYPOTENSION, BRADYCARDIA, AND SYNCOPE; SEIZURE; MYOCARDITIS, PERICARDITIS, AND CARDIOMYOPATHY; INCREASED MORTALITY IN E |
Signals both drugs share
| Reaction | Clonazepam | Clozapine | Label screen (A / B) |
|---|---|---|---|
| Psychiatric decompensation | 255 · PRR 19.7 | 465 · PRR 52.4 | Not in label — unassessed / Not in label — unassessed |
Labeled signals distinctive to Clonazepam
- Rhinitis allergic — n=479, PRR 15.8 Labeled (related wording)
- Substance use disorder — n=301, PRR 14.2 Labeled adverse reaction
- Depression suicidal — n=229, PRR 9.3 Labeled (related wording)
- Depressive symptom — n=219, PRR 8.7 Labeled adverse reaction
- Hostility — n=144, PRR 7.8 Labeled adverse reaction
Labeled signals distinctive to Clozapine
- Granulocytopenia — n=2,616, PRR 141.2 Labeled adverse reaction
- Myocarditis — n=2,231, PRR 41.1 Labeled — boxed warning
- Salivary hypersecretion — n=1,844, PRR 37.9 Labeled adverse reaction
- Psychotic symptom — n=370, PRR 37.1 Labeled adverse reaction
- Benign ethnic neutropenia — n=114, PRR 1,565.3 Labeled — boxed warning
- Rebound psychosis — n=79, PRR 99.4 Labeled (related wording)
Common questions
Which has more reported side effects, Clonazepam or Clozapine?
Clonazepam has 159,258 FAERS reports and Clozapine 124,826. 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 (68% vs 95%) is a better like-for-like signal of the kind of problems reported.
Which side effects do Clonazepam and Clozapine share?
Both drugs carry disproportionality signals for psychiatric decompensation. Shared signals often reflect a shared drug class or the condition both are used for.
Is Clonazepam or Clozapine 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.