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Tizanidine Side Effects

Medically reviewed by Last updated on Aug 15, 2023.


Commonly reported side effects of tizanidine include: bradycardia, dizziness, drowsiness, hypotension, asthenia, fatigue, and xerostomia. Other side effects include: constipation, and increased liver enzymes. Continue reading for a comprehensive list of adverse effects.

Applies to tizanidine: oral capsules and tablets.

Side effects include:

Dry mouth, somnolence, asthenia (weakness, fatigue, and/or tiredness), dizziness.

For Healthcare Professionals

Applies to tizanidine: oral capsule, oral tablet.


The most frequently reported adverse reactions include dry mouth, somnolence/sedation, asthenia, and dizziness.[Ref]

Nervous system

Very common (10% or more): Somnolence (up to 48%), dizziness (up to 16%)

Common (1% to 10%): Speech disorder, dyskinesia

Frequency not reported: Headache, ataxia, dysarthria

Postmarketing reports: Convulsion, paresthesia, tremor[Ref]


Very common (10% or more): Dry mouth (up to 49%)

Common (1% to 10%): Vomiting, constipation

Rare (0.01% to 0.1%): Nausea, gastrointestinal disorder

Frequency not reported: Abdominal pain, loss of appetite[Ref]


Common (1% to 10%): Liver test abnormality

Very rare (less than 0.01%): Hepatic failure

Frequency not reported: Hepatotoxicity

Postmarketing reports: Hepatitis[Ref]


Common (1% to 10%): Bradycardia, hypotension, tachycardia

Postmarketing reports: Syncope, ventricular tachycardia, QT prolongation[Ref]


Common (1% to 10%): Amblyopia

Frequency not reported: Accommodation disorder[Ref]


Frequency not reported: Pruritus

Postmarketing reports: Stevens Johnson Syndrome, exfoliative dermatitis, rash[Ref]


Common (1% to 10%): Fatigue

Frequency not reported: Drug withdrawal reactions including rebound hypertension, tachycardia, and hypertonia[Ref]


Common (1% to 10%): Urinary tract infection, urinary frequency[Ref]


Common (1% to 10%): Pharyngitis, rhinitis[Ref]


Frequency not reported: Anaphylaxis, hypersensitivity reactions

Postmarketing reports: Anaphylactic Reaction[Ref]


Common (1% to 10%): Infection, flu syndrome[Ref]


Rare (0.01% to 0.1%): Muscular weakness

Postmarketing reports: Arthralgia[Ref]


Common (1% to 10%): Nervousness

Rare (0.01% to 0.1%): Hallucinations, insomnia, sleep disorders

Frequency not reported: Confusional state

Postmarketing reports: Depression[Ref]

Frequently asked questions


1. Product Information. Zanaflex (tizanidine). Acorda Therapeutics. 2001.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.