ZANAFLEX CAPSULES® <small>(tizanidine HCl)</small>

Click here to see Important Safety Information below

ZANAFLEX CAPSULES is a short-acting drug for the management of spasticity. Because of the short duration of effect, treatment with tizanidine should be reserved for those daily activities and times when relief of spasticity is most important. Spasticity is a frequent and often significant consequence of injuries to the central nervous system, including multiple sclerosis (MS), spinal cord injury (SCI), brain trauma and stroke. People with spasticity can suffer severe, painful muscle spasms and/or rigidity during the day and night. ZANAFLEX CAPSULES are thought to reduce spasticity by blocking nerve impulses through pre-synaptic inhibition of motor neurons, which decreases spasticity without reducing muscle strength.

While ZANAFLEX CAPSULES and ZANAFLEX® (tizanidine hydrochloride) TABLETS both contain tizanidine hydrochloride, ZANAFLEX CAPSULES are not the same as or bioequivalent to generic tizanidine tablets or ZANAFLEX TABLETS. Food has a complex effect on how tizanidine is absorbed and processed in the body, so ZANAFLEX CAPSULES are not interchangable with ZANAFLEX TABLETS or generic tizanidine tablets.

A person’s experience taking ZANAFLEX CAPSULES may change depending on whether or not this medication is taken with or without food, including potential changes in efficacy and side effects. It is important that patients follow their doctor’s instructions on how to take this medication.

ZANAFLEX CAPSULES are available in 2-mg, 4-mg and 6-mg strengths.

ZANAFLEX CAPSULES can give physicians and patients greater flexibility in managing spasticity. Some patients may find capsules easier to take than tablets and, for patients who have an impaired ability to swallow, capsules can be opened and sprinkled on soft foods such as applesauce. This is not bioequivalent to administration of an intact capsule. In addition, the 6-mg dose, which is not available in a tablet form, may provide the opportunity for patients to take fewer pills per day.

Important Safety Information for ZANAFLEX CAPSULES:

  • 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
  • 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 delusion 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

For Full Prescribing Information, please click here.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

ZANAFLEX CAPSULES® and ZANAFLEX® are registered trademarks of Acorda Therapeutics, Inc.