Facts About Tizanidine HCL

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Patients with multiple sclerosis or spinal injury are directed to ingest this medication to help with cramping or spasms of muscles as well as tightness of the muscles. This is a short acting muscle relaxer that helps by blocking signals from the spine to the brain called alpha adrenergic agonists. Multiple sclerosis causes tightening of the muscles, as does spinal injuries, causing this medication to be of the utmost help with the pain associated with these troubles.


Dosing Information

Doses are determined by physician, according to severity of tightening and need of relaxation. This medication is taken orally, and the dosage will be increased gradually until side effects therapy causes it to be stopped. Starting within 2 hours of dosing, tizanidine HCL wears off in 6 to 8 hours and can be taken at these intervals. There should be no more than 36 mg taken daily, or no more than 3 doses in 24 hours.


Patients who are on anti-depressants or anti-anxiety medication as well as those with high or low blood pressure, kidney disease or liver disease including Long QT Syndrome should not take this medication according to Drugs.com. Any patient that is not able to use zanaflex due to allergic reactions to other muscle relaxers or any of the ingredients in this medication should be monitored if this is prescribed.

Drug Interactions

Drugs including atniarhythmics like amiodarone, mexiletine, propafenone, verapamil, birth control pills, blood pressure drugs like ACE inhibitors, cimetidine, liver enzyme acting drugs like ticlopidine, acyclovir, fluroquinolone, furosemide and thiazides as well as beta blockers including guanfacine, guanabenz and clonidine should be avoided. All medications taken during treatment with tizanidine HCL should be reported to a doctor prior to starting this drug. Narcotic pain relievers, tricyclic drugs, tranquilizers, anti-anxiety drugs and antihistamines should also be avoided.

Side Effects of Tizanidine HCL

Side effects include constipation, dry mouth and drowsiness, dizziness, weakness and fatigue as well as headache. To relieve the dry mouth associated with this drug, simply suck on sugarless hard candy or ice chips, or drink water. More serious side effects that should be reported to a doctor immediately include seeing things that aren’t there, burning urination, hearing or vision changes like blurred vision and fainting or mental and mood changes.


Zanaflex should not be taken with sleeping pills or other muscle relaxers, or more than 36 mg daily taken as these can cause permanent liver damage. Sleeping pills, seizure medications and depression medications can be increased while using this drug. This drug is in the FDA’s category C for pregnancy, meaning that this may be harmful to unborn babies. It is not known if this can be passed through breast milk, so those breast feeding mothers should consult a physician prior to feeding.


RXList.com from the publication Zanaflex (tizanidine hydrochloride) publication date unknown.

Drug.com from the publication Zanaflex last updated April 12, 2009.