Note: This document contains side effect information about tizanidine. Some dosage forms listed on this page may not apply to the brand name Zanaflex.

Summary

Common side effects of Zanaflex 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.

General

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]

Gastrointestinal

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]

Hepatic

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

Very rare (less than 0.01%): Hepatic failure

Frequency not reported: Hepatotoxicity

Postmarketing reports: Hepatitis^[Ref]

Cardiovascular

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

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

Ocular

Common (1% to 10%): Amblyopia

Frequency not reported: Accommodation disorder^[Ref]

Dermatologic

Frequency not reported: Pruritus

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

Other

Common (1% to 10%): Fatigue

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

Genitourinary

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

Respiratory

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

Hypersensitivity

Frequency not reported: Anaphylaxis, hypersensitivity reactions

Postmarketing reports: Anaphylactic Reaction^[Ref]

Immunologic

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

Musculoskeletal

Rare (0.01% to 0.1%): Muscular weakness

Postmarketing reports: Arthralgia^[Ref]

Psychiatric

Common (1% to 10%): Nervousness

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

Frequency not reported: Confusional state

Postmarketing reports: Depression^[Ref]