Zanaflex - National Multiple Sclerosis Society

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About this Medication
  • Brand Name: Zanaflex (U.S. and Canada)
  • Chemical Name: tizanidine hydrochloride (tye-ZAN-i-deen)
  • Usage in MS: Spasticity
  • Generic Available: Yes


Tizanidine is used in multiple sclerosis to treat the increased muscle tone associated with spasticity. While it does not provide a cure for the problem, it is designed to relieve the spasms, cramping, and tightness of muscles.

Proper Usage

Tizanidine is a short-acting drug for the management of spasticity. Its peak effectiveness occurs one to two hours after dosing, and is finished between three to six hours after dosing. Therefore, your physician will prescribe a dosing schedule that provides maximal relief during activities and periods of time of greatest importance to you.

In order to minimize unwanted side effects with this medication, your physician will start you on a low dose and gradually raise it until a well-tolerated and effective level is reached.


  • Before starting this medication, let your doctor know if you have experienced any liver or kidney problems, or if you are taking any kind of blood pressure medication.
  • Since 2005, this medication has been available in three forms—as a capsule (Zanaflex Capsules™), a pill (Zanaflex®), and in generic form (tizanidine). Although the three forms have the same active ingredient (tizanidine hydrochloride) the formulations are somewhat different. Therefore, Zanaflex Capsules are not interchangeable with Zanaflex tablets or the generic drug. If your physician has prescribed Zanaflex Capsules it is important to know that switching from the capsule to a tablet may increase the risk of certain side effects. Please consult with your prescribing physician before allowing a switch from Zanaflex Capsules to a tablet formulation.
  • Tizanidine should not be used in combination with fluvoxamine (Luvox®--an SSRI antidepressant) or ciprofloxacin (Cipro®--an antibiotic medication used in MS to treat urinary tract infections) because a sudden and significant drop in blood pressure can occur.
  • Oral contraceptives (birth control pills) may slow the release of tizanidine from the body; women using birth control pills should inform their physician so that the dose level of tizanidine can be reduced accordingly.
  • This medication may cause blurred vision*, dizziness, or drowsiness in some people.
  • This drug will add to the effects of alcohol and other central nervous system (CNS) depressants (such as antihistamines, sedatives, tranquilizers, prescription pain medications, seizure medications, other muscle relaxants), possibly causing drowsiness. Be sure that your physician knows if you are taking these or any other medications.
  • Studies of tizanidine have not been done in pregnant women. Animal studies, using doses significantly higher than those prescribed for humans, have resulted in damage to the offspring. If you are pregnant or planning to become pregnant, discuss this with your physician before starting this medication.
  • It is not known whether tizanidine passes into the breast milk. Women should not take this medication while nursing unless told to do so by their physician.

Possible Side Effects

Common side effects that may go away as your body adjusts to the medication and do not require medical attention unless they continue for more than two weeks or are bothersome: dryness of mouth; sleepiness or sedation; weakness*; fatigue*, and or tiredness*; dizziness or lightheadedness, especially when getting up from a sitting or lying position; increase in muscle spasms, cramps or tightness; back pain.

Common side effects that should be reported to the doctor as soon as possible: burning, prickling, or tingling sensation*; diarrhea; fainting; fever; loss of appetite; nausea; nervousness; pain or burning during urination; sores on skin; stomach pain; vomiting; yellow eyes or skin; blurred vision*.

* Since it may be difficult to distinguish between certain common symptoms of MS and some side effects of tizanidine, be sure to consult your health care professional if an abrupt change of this type occurs.