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Chlorzoxazone Side Effects

The most commonly reported side effects of chlorzoxazone include fatigue, dizziness, and nausea, based on 1,955 FDA adverse event reports from 2004 to 2025. 5.6% of reports found the drug to be ineffective.

Chlorzoxazone side effects

Percentages show how often each reaction appears relative to total reports for chlorzoxazone.

1
Fatigue6.9%134
2
Dizziness6.1%120
3
Nausea5.7%112
4
Drug Ineffective5.6%110
5
Pain5.5%108
6
Headache5.2%101
7
Anxiety3.6%70
8
Intentional Overdose3.6%70
9
Drug Hypersensitivity3.3%64
10
Somnolence3.2%63
11
Dyspnoea3.1%60
12
Chronic Kidney Disease3.0%58
13
Fall2.9%56
14
Diarrhoea2.8%54
15
Arthralgia2.7%52

These are voluntary reports and do not establish that chlorzoxazone caused these reactions.

Report severity

65.3%Serious1,277 reports
30.0%Hospitalizations587 reports
8.8%Fatal173 reports

Seriousness is determined by the reporter, not by OpenClaim.

Chlorzoxazone drug interactions

Other drugs that appear in adverse event reports alongside chlorzoxazone. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Sodium-oxybate7.0%136
2
Acetaminophen4.7%91
3
Tramadol-hydrochloride4.0%79
4
Omeprazole3.9%77
5
Gabapentin3.8%75
6
Adalimumab3.3%64
7
Oxycodone3.2%63
8
Esomeprazole3.1%60
9
Pregabalin2.7%52
10
Promethazine-hydrochloride2.4%46
11
Naproxen2.3%45
12
Hydrocodone2.1%42
13
Zolpidem-tartrate2.1%42
14
Fentanyl1.8%36
15
Ibuprofen1.8%36

Taken alongside

1
Acetaminophen28.3%553
2
Gabapentin19.6%383
3
Ergocalciferol15.6%305
4
Omeprazole14.0%274
5
Ibuprofen13.6%265
6
Albuterol13.2%259
7
Hydrocodone13.1%256
8
Oxycodone13.1%256
9
Aspirin12.9%253
10
Levothyroxine-sodium12.2%239
11
Fluticasone11.3%221
12
Prednisone11.0%216
13
Tramadol-hydrochloride10.5%206
14
Duloxetine-hydrochloride10.4%204
15
Alprazolam9.5%185

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports chlorzoxazone side effects

69.8% of chlorzoxazone adverse event reports involve female patients and 23.5% involve male patients. The largest age group is adult at 73%. These figures reflect who reports side effects, not underlying risk.

Sex

Female69.8%
Male23.5%
Unknown6.8%

Age group

< 20.0%
2–110.1%
12–170.1%
18–6472.7%
65+27.0%

What is chlorzoxazone used for

Conditions and purposes for which patients were taking chlorzoxazone when the adverse event was reported.

Abdominal Pain UpperAnalgesic TherapyAnkylosing SpondylitisArthralgiaArthritisArthralgiaArthritisBack DisorderBack InjuryBack PainBone PainBreakthrough PainBack DisorderBack PainCerebrovascular Disorder

Showing 15 of 104 indications

Chlorzoxazone brand names and reporting trend

Chlorzoxazone is sold under the brand name Strifon Forte Dsc.

Brand names

Strifon Forte Dsc1,394

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking chlorzoxazone with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.