Zanaflex

DRUG DESCRIPTION

Zanaflex® (tizanidine hydrochloride) is a centrally acting ?2-adrenergic agonist. Tizanidine HCl (tizanidine) is a white to off-white, fine crystalline powder, which is odorless or with a faint characteristic odor. Tizanidine is slightly soluble in water and methanol; solubility in water decreases as the pH increases. Its chemical name is 5-chloro-4-(2-imidazolin-2-ylamino)-2,1,3-benzothiodiazole hydrochloride. Tizanidine's molecular formula is C9H8CIN5 S-HCl, its molecular weight is 290.2 and its structural formula is:

Zanaflex (tizanidine hydrochloride) structural formula illustration

Zanaflex Capsules™ (tizanidine) are supplied as 2, 4, and 6 mg capsules and Zanaflex (tizanidine) ® tablets are supplied as 2 and 4 mg tablets for oral administration. Zanaflex (tizanidine) Capsules™ are composed of the active ingredient, tizanidine hydrochloride (2.29 mg equivalent to 2 mg tizanidine base, 4.58 mg equivalent to 4 mg tizanidine base, and 6.87 mg equivalent to 6 mg tizanidine base), and the inactive ingredients, hydroxypropyl methyl cellulose, silicon dioxide, sugar spheres, titanium dioxide, gelatin, and colorants.

Zanaflex (tizanidine) ® tablets are composed of the active ingredient, tizanidine hydrochloride (2.29 mg equivalent to 2 mg tizanidine base and 4.58 mg equivalent to 4 mg tizanidine base), and the inactive ingredients, silicon dioxide colloidal, stearic acid, microcrystalline cellulose and anhydrous lactose.

What are the possible side effects of tizanidine (Zanaflex)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • feeling light-headed, fainting, slow heart rate;
  • hallucinations, confusion, unusual thoughts or behavior;
  • nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
  • burning or pain when you...

Read All Potential Side Effects and See Pictures of Zanaflex »

What are the precautions when taking tizanidine (Zanaflex)?

Before taking tizanidine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: low blood pressure or heart disease, kidney disease, liver disease.

This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Avoid alcoholic beverages.

To minimize dizziness, stand up slowly when arising from a sitting or lying position.

Caution is...

Read All Potential Precautions of Zanaflex »


Zanaflex Consumer (continued)

SIDE EFFECTS: Constipation, dry mouth, drowsiness, dizziness, weakness and fatigue may occur. If any of these effects persist or worsen, contact your doctor or pharmacist promptly.

To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: fainting, mental/mood changes including seeing things that aren't there, frequent/burning urination, hearing or vision changes such as blurred vision.

Tell your doctor immediately if any of these rare but very serious side effects occur: black stool, slow or irregular heartbeat.

Tizanidine rarely has caused very serious (possibly fatal) liver disease. Tell your doctor immediately if you develop symptoms of liver disease, including persistent nausea, stomach/abdominal pain, dark urine, yellowing eyes/skin.

A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking tizanidine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: low blood pressure or heart disease, kidney disease, liver disease.

This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Avoid alcoholic beverages.

To minimize dizziness, stand up slowly when arising from a sitting or lying position.

Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially dizziness and drowsiness.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

It is not known whether this drug is excreted into human milk. Consult your doctor before breast-feeding.


Zanaflex Patient Information Including Side Effects

Brand Names: Zanaflex

Generic Name: tizanidine (Pronunciation: tye ZAN i deen)

  • What is tizanidine (Zanaflex)?
  • What are the possible side effects of tizanidine (Zanaflex)?
  • What is the most important information I should know about tizanidine (Zanaflex)?
  • What should I discuss with my healthcare provider before taking tizanidine (Zanaflex)?
  • How should I take tizanidine (Zanaflex)?
  • What happens if I miss a dose (Zanaflex)?
  • What happens if I overdose (Zanaflex)?
  • What should I avoid while taking tizanidine (Zanaflex)?
  • What other drugs will affect tizanidine (Zanaflex)?
  • Where can I get more information?

What is tizanidine (Zanaflex)?

Tizanidine is a short-acting muscle relaxer. It works by blocking nerve impulses (pain sensations) that are sent to your brain.

Tizanidine is used to treat spasticity by temporarily relaxing muscle tone.

Tizanidine may also be used for purposes other than those listed in this medication guide.

What are the possible side effects of tizanidine (Zanaflex)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • feeling light-headed, fainting, slow heart rate;
  • hallucinations, confusion, unusual thoughts or behavior;
  • nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
  • burning or pain when you urinate.

Less serious side effects may be more likely to occur, such as:

  • drowsiness or dizziness;
  • feeling anxious or nervous;
  • numbness or tingling;
  • stomach pain, diarrhea, constipation, vomiting;
  • fever;
  • dry mouth;
  • muscle weakness, back pain;
  • increased muscle tone or spasms; or
  • sweating or skin rash.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about tizanidine (Zanaflex)?

Tizanidine is a short-acting medication that should be taken only for daily activities that require relief from muscle spasticity.

Do not take tizanidine if you are also taking the antidepressant fluvoxamine (Luvox), or the antibiotic ciprofloxacin (Cipro).

Do not use tizanidine at a time when muscle tone is needed to assure safe balance and movement for certain activities. In some situations, it may endanger your physical safety to be in a state of reduced muscle tone.

Switching between tizanidine tablets and capsules, or changing the way you take it with regard to eating, can cause an increase in side effects or a decrease in therapeutic effect. Follow your doctor's instructions carefully. After making any changes in how you take tizanidine, contact your doctor if you notice any change in how well the medicine works or if it causes increased side effects.

Do not take more than three doses (36 mg) of tizanidine in a 24-hour period. Too much of this medication can damage your liver.

Cold or allergy medicine, narcotic pain medicine, sleeping pills, other muscle relaxers, and medicine for seizures, depression or anxiety can add to sleepiness caused by tizanidine. Tell your doctor if you need to use any of these other medicines together with tizanidine.

Avoid drinking alcohol. It can increase some of the side effects of tizanidine.

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