About Spasticity

Spasticity refers to the involuntary tension, stiffening or contractions of muscles

This condition occurs when some of the nerve cells in the spinal cord do not respond to control from the brain.


Spasticity may be painful and may range from slight muscle stiffness to permanent shortening of the muscle. Spasticity may interfere with mobility, making moving from a seated to a standing position or transferring from a bed to a wheelchair more difficult. Daily activities such as eating, dressing and grooming may also become more difficult for a person living with spasticity.


Spasticity is common in neurological disorders where portions of the nervous system that control voluntary movement have been damaged, such as spinal cord injury (SCI), multiple sclerosis (MS), stroke and traumatic brain injury.


While the incidence of spasticity is not known with certainty, it is estimated to affect over half a million people in the United States alone, and over 12 million worldwide.


The majority of people (greater than 85%) with MS experience some form of spasticity.



Please see below for Important Safety Information.
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Be sure you received what your doctor ordered.


Zanaflex Capsules® (tizanidine hydrochloride) is a short-acting drug indicated for the management of spasticity. Because of the short duration of effect, treatment with Zanaflex Capsules® (tizanidine hydrochloride) should be reserved for those daily activities and times when relief of spasticity is most important.

Important Safety Information:

  • Use with fluvoxamine or ciprofloxacin is contraindicated and results in significant increases in tizanidine plasma levels.
  • There is a limited data base for chronic use of single doses above 8 mg and multiple doses above 24 mg per day.
  • Tizanidine is an alpha2-adrenergic agonist and can produce hypotension. In a single-dose study where patients were not titrated, two-thirds of patients given 8 mg of Zanaflex experienced hypotension, which may be minimized by titration of dose. The hypotensive effect is dose related and has been measured following single doses of 2 mg or more.
  • Tizanidine occasionally causes liver injury, most often of the hepatocellular type.
  • Patients should be advised that sedation may interfere with daily activities. These effects appear to be dose related.
  • Visual hallucinations or delusions occurred in 3% (5/170) of study patients in two North American clinical trials.
  • Use with caution in hepatic or renally impaired patients.
  • Use with oral contraceptives results in 50% decrease in tizanidine clearance.
  • To discontinue therapy, taper the dose in patients receiving high doses over long time periods to reduce the risk of hypertension, tachycardia and hypertonia.
  • In vitro studies indicate that neither tizanidine nor the major metabolites are likely to affect the metabolism of other drugs metabolized by cytochrome P450 isoenzymes.
  • Most common adverse events with tizanidine include dry mouth (49%), somnolence (48%), asthenia [weakness, fatigue and/or tiredness] (41%), dizziness (16%) and increased ALT (5%). Other adverse events include UTI, infection and constipation.
  • Food has complex effects on tizanidine pharmacokinetics, which differ for the different formulations. These pharmacokinetic differences may result in clinically significant differences when switching formulations, or changing administration during a fed or fasted state. These changes may result in increased adverse events or a delayed/more rapid onset of activity, depending on the nature of the switch.
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