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Tizanidine Side Effects

The most commonly reported side effects of tizanidine include fatigue, pain, and nausea, based on 46,232 FDA adverse event reports from 2004 to 2025. 6.1% of reports found the drug to be ineffective.

Tizanidine side effects

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

1
Fatigue6.8%3,155
2
Pain6.3%2,927
3
Nausea6.2%2,875
4
Drug Ineffective6.1%2,806
5
Headache5.7%2,621
6
Fall5.0%2,301
7
Diarrhoea4.2%1,925
8
Dizziness3.9%1,820
9
Off Label Use3.4%1,562
10
Arthralgia3.4%1,552
11
Dyspnoea3.3%1,511
12
Vomiting3.2%1,484
13
Asthenia3.2%1,473
14
Chronic Kidney Disease3.1%1,422
15
Anxiety2.9%1,350

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

Report severity

60.7%Serious28,056 reports
28.7%Hospitalizations13,252 reports
6.6%Fatal3,064 reports

Seriousness is determined by the reporter, not by OpenClaim.

Tizanidine drug interactions

Other drugs that appear in adverse event reports alongside tizanidine. 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-oxybate5.4%2,503
2
Dalfampridine5.0%2,310
3
Pregabalin4.4%2,043
4
Adalimumab4.2%1,960
5
Dimethyl3.7%1,727
6
Interferon3.4%1,588
7
Esomeprazole3.0%1,383
8
Omeprazole3.0%1,368
9
Baclofen2.7%1,254
10
Gabapentin2.7%1,233
11
Lenalidomide2.6%1,179
12
Dupilumab2.3%1,055
13
Fingolimod2.2%995
14
Ocrelizumab2.1%966
15
Pantoprazole-sodium2.0%941

Taken alongside

1
Gabapentin27.3%12,640
2
Acetaminophen26.5%12,256
3
Ergocalciferol21.9%10,147
4
Levothyroxine-sodium15.7%7,246
5
Omeprazole15.4%7,111
6
Albuterol15.2%7,048
7
Oxycodone14.8%6,861
8
Aspirin14.4%6,663
9
Hydrocodone13.4%6,179
10
Duloxetine-hydrochloride13.1%6,067
11
Fluticasone12.5%5,802
12
Atorvastatin-calcium11.8%5,443
13
Ibuprofen11.7%5,420
14
Tramadol-hydrochloride11.4%5,276
15
Baclofen11.1%5,110

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 tizanidine side effects

71.7% of tizanidine adverse event reports involve female patients and 22.5% involve male patients. The largest age group is adult at 75%. These figures reflect who reports side effects, not underlying risk.

Sex

Female71.7%
Male22.5%
Unknown5.8%

Age group

< 20.2%
2–110.4%
12–170.5%
18–6475.3%
65+23.7%

What is tizanidine used for

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

Abdominal DiscomfortAbdominal PainAccidental ExposureAdjuvant TherapyAdvanced Sleep PhaseAffective DisorderAllergenic Desensitisation ProcedureAlopeciaAmputation Stump PainAmyotrophic Lateral SclerosisAnaemiaAnalgesic Intervention Supportive TherapyAnalgesic TherapyAnkylosing SpondylitisAntiinflammatory Therapy

Showing 15 of 593 indications

Tizanidine brand names and reporting trend

Tizanidine is sold under the brand name Zanaflex.

Brand names

Zanaflex135

Quarterly reports (20042025)

20052010201520202025

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

Taking tizanidine with another medication?

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