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clonazepam Side Effects

Also known as: Klonopin

Analysis of 155,147 adverse event reports submitted to the FDA from 2002 to 2025.

Total Reports

155,147

Death-Related

18,179

11.7% of reports

Hospitalizations

46,031

29.7% of reports

Top Indication

Product Used For Unknown Indication

Most Reported Adverse Reactions

DRUG INEFFECTIVE
13,608
FATIGUE
10,236
NAUSEA
9,564
ANXIETY
8,735
HEADACHE
8,590
DEPRESSION
8,121
PAIN
8,033
OFF LABEL USE
7,662
DIZZINESS
7,245
INSOMNIA
7,008
DYSPNOEA
6,826
FALL
6,625
DIARRHOEA
6,606
VOMITING
6,214
MALAISE
5,976
SOMNOLENCE
5,590
TOXICITY TO VARIOUS AGENTS
5,182
ASTHENIA
4,972
COMPLETED SUICIDE
4,893
PNEUMONIA
4,840

Who Reports Side Effects

Gender Distribution

Female 93,695 (65%)
Male 50,940 (35%)
Unknown 291

Age Distribution

0-17 5,099 (5%)
18-44 30,476 (30%)
45-64 42,428 (42%)
65-74 15,408 (15%)
75+ 8,289 (8%)

Reporting Trend by Year

2002 2025

Reactions in Death Reports

Top reactions reported in 18,179 reports where death was an outcome. These are voluntarily reported and do not establish causation.

Reaction Reports
COMPLETED SUICIDE 4,873
DEATH 4,159
TOXICITY TO VARIOUS AGENTS 3,552
CARDIAC ARREST 1,504
DRUG ABUSE 1,409
CARDIO-RESPIRATORY ARREST 1,405
RESPIRATORY ARREST 1,092
OVERDOSE 969
DRUG INTERACTION 651
PNEUMONIA 592
DEPRESSION 502
OFF LABEL USE 443
POISONING 394
PULMONARY OEDEMA 377
RESPIRATORY FAILURE 371
DYSPNOEA 369
HYPOTENSION 363
FALL 352
DRUG DEPENDENCE 344
UNRESPONSIVE TO STIMULI 326

Reactions in Hospitalization Reports

Top reactions in 46,031 reports where hospitalization was an outcome.

Reaction Reports
FALL 3,372
PNEUMONIA 3,043
ANXIETY 3,014
NAUSEA 2,962
DRUG INEFFECTIVE 2,891
DEPRESSION 2,820
DYSPNOEA 2,787
FATIGUE 2,745
PAIN 2,701
VOMITING 2,676
OFF LABEL USE 2,533
HEADACHE 2,446
DIARRHOEA 2,330
DIZZINESS 2,124
ASTHENIA 2,095
PYREXIA 2,078
DRUG INTERACTION 2,015
MALAISE 1,974
INSOMNIA 1,891
TOXICITY TO VARIOUS AGENTS 1,838

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What the FAERS Data Reveals About clonazepam Side Effects

The FDA Adverse Event Reporting System (FAERS) contains 155,147 voluntary reports linked to clonazepam and its brand equivalents (Klonopin), spanning 2002 through 2025. Of those, 18,179 (11.7%) listed death as an outcome and 46,031 (29.7%) 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, 65% were female and 35% male; age distribution skews toward 45-64, with 42,428 reports in that bracket. The single most reported reaction is drug ineffective with 13,608 submissions, followed by fatigue and nausea.

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.