What is tizanidine used for?

What Tizanidine Is Used For

Tizanidine is a centrally acting muscle relaxant FDA-approved for managing spasticity (increased muscle tone) associated with upper motor neuron disorders such as stroke, multiple sclerosis, and spinal cord injury. 1

Primary FDA-Approved Indication

• Tizanidine is specifically indicated for the management of spasticity, which is characterized by increased muscle tone resulting from upper motor neuron syndromes 1
• The FDA label emphasizes that tizanidine is a short-acting drug that should be reserved for daily activities and times when relief of spasticity is most important 1
• The American Heart Association recommends tizanidine for treating spasticity that results in pain, poor skin hygiene, or decreased function in patients with chronic stroke 2

Specific Conditions Where Tizanidine Is Effective

Spasticity from Neurological Disorders

• Multiple sclerosis: Clinical trials demonstrate a 20% mean reduction in muscle tone with doses of 24-36 mg daily, with approximately 75% of patients reporting subjective improvement 3
• Spinal cord injury: Tizanidine significantly reduces muscle tone as measured by Ashworth scores (p = 0.0001) compared to placebo, without causing significant alterations in muscle strength 4
• Acquired brain injury and stroke: The medication is effective across various cerebral injuries causing spasticity 2, 5

Off-Label Uses (Not FDA-Approved)

• Acute low back pain: The American College of Physicians recognizes tizanidine as an option for short-term relief of acute low back pain, though clinical trial durations were typically 2 weeks or less 2
• Pain syndromes: Evidence supports use in myofascial pain, lower back pain, and trigeminal neuralgia, though these are not FDA-approved indications 6

Mechanism of Action

• Tizanidine functions as a centrally acting alpha-2 adrenergic receptor agonist that reduces muscle tone without significantly affecting muscle strength 2, 5
• Maximum effects occur within 2 hours of administration, with clinical trials showing reduction in mean muscle tone scores of 21-37% versus 4-9% for placebo 5

Important Clinical Distinctions

• Tizanidine treats spasticity (increased muscle tone), NOT hypotonia (reduced muscle tone) - using it for hypotonia would be inappropriate and potentially harmful 7
• Unlike benzodiazepines such as diazepam, tizanidine is not contraindicated during stroke recovery 2
• Subjective muscle weakness is reported less often with tizanidine compared to baclofen or diazepam, making it advantageous when preserving functional strength is important 5

Dosing Considerations

• Starting dose is 2 mg up to three times daily, particularly in older adults or those with renal impairment 2
• Optimal dosage must be titrated over 2-4 weeks for each patient, with effective doses ranging from 2-36 mg/day due to wide interpatient variability 5
• Older adults rarely tolerate doses greater than 30-40 mg per day 8

Critical Safety Warnings

• Hypotension: Tizanidine can cause significant hypotension requiring monitoring 2, 8
• Avoid abrupt discontinuation: In long-term users, taper slowly to prevent withdrawal symptoms including tachycardia, hypertension, and rebound hypertonia 8
• Common adverse effects: Dry mouth and somnolence/drowsiness are the most frequently reported side effects 5, 4
• Use with caution in hepatic or renal dysfunction due to reduced clearance 8