TIZANIDINE (Zanaflex): What is used for?

What is Tizanidine?

Tizanidine is a drug used to treat muscle spasms. The product ingredient is Tizanidine hydrochloride (hcl).
The brand name of Tizanidine in the United States is Zanaflex.

Mechanism of Action (MOA) 

Alpha-2-adrenergic receptor agonist that appears to reduce spasticity by increasing presynaptic inhibition of motor neurons.

Therapeutic indications, uses, benefits and dosage of Tizanidine


Painful muscle spasms associated with static and functional disorders of the spine (cervical and lumbar syndromes), or after surgery (herniated intervertebral disc or osteoarthritis of the hip): 2-4 mg/8 h; severe cases additional dose: 2 or 4 mg per night.

Spasticity due to neurological disorders (multiple sclerosis, chronic myelopathy, degenerative spinal cord disorders, stroke, cerebral palsy): initial 2 mg/8 h, increasing every 3-7 days by 2-4 mg until reaching 12-24 mg/day in 3 or 4 doses; max. 36 mg/day.
Renal insufficiency (Clcr < 25 ml/min): initial 2 mg/day, adjust according to response and tolerance.

Mode of administration 

Oral use. Take the tablets with a glass of water.

Contraindications of Tizanidine

Hypersensitivity, concomitant administration with fluvoxamine or ciprofloxacin.

Warnings and Precautions with Tizanidine

  • Liver failure (impaired liver function), elderly.
  • Hypotension (loss of consciousness and circulatory collapse) may occur.
  • Do not interrupt abruptly (rebound hypertension and tachycardia).
  • Periodic hepatic control. Risk of sedation (50%) and hallucinations (3%).
  • Not recommended for children.
  • Avoid concomitant use with other CYP1A2 inhibitors.

Liver failure

Begin treatment with lower doses and increase as a function of tolerability.

Renal insufficiency

Caution. Start treatment with a dose of 2 mg/day and adjust the dose according to response and tolerance.


Increased action by: amiodarone, mexiletine, propafenone, cimetidine, enoxacin, pefloxacin, ciprofloxacin, norfloxacin, rofecoxib, oral contraceptives and ticlopidine.


No clinical data are available in humans.

It should not be used unless the benefit clearly outweighs the risks.


It is not known whether tizanidine is excreted by milk in humans, although it is known that in animals it passes into milk in small amounts.

It is not recommended during breast-feeding.

Effects on driving ability

This active ingredient may cause drowsiness, dizziness, or other signs or symptoms of hypotension, so driving vehicles or operating machinery while taking this medication is not recommended.

Adverse reactions and side effects of Tizanidine

Drowsiness, dizziness; bradycardia; hypotension; dry mouth; fatigue; decreased blood pressure.


Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).

In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.


PubChem CID: 5487
NCI Thesaurus: C61976

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