Uses
What is tizanidine used for?
Tizanidine is commonly used for muscle spasticity, including muscle spasms.
Tizanidine may also be used for other conditions as determined by your healthcare provider.
How does tizanidine work (mechanism of action)?
Tizanidine works by reducing nerve activity in the spinal cord. This helps to relax the muscles and lead to reduced muscle spasms.
How is tizanidine supplied (dosage forms)?
Tizanidine is available as Zanaflex and generic tizanidine in the following dosage forms that are taken by mouth.
- 2 mg oral capsules
- 4 mg oral capsules
- 6 mg oral capsules
- 2 mg oral tablets
- 4 mg oral tablets
How should I store tizanidine?
Tizanidine should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.
Side Effects
What are the most common side effects of tizanidine?
The most common side effects of tizanidine are listed below. Tell your healthcare provider if you have any of these side effects that bother you.
- Dry mouth
- Drowsiness or sleepiness (see below)
- Feeling unusually weak or tired
- Dizziness (see below)
- Kidney or bladder infection
- Constipation
- Vomiting
- Common cold symptoms
There may be other side effects of tizanidine that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What are the serious side effects of tizanidine?
While less common, the most serious side effects of tizanidine are described below, along with what to do if they happen.
Severe Allergic Reactions. Tizanidine may cause allergic reactions, which can be serious. Stop taking tizanidine and get help right away if you have any of the following symptoms of a serious allergic reaction.
- Breathing problems or wheezing
- Racing heart
- Fever or general ill feeling
- Swollen lymph nodes
- Swelling of the face, lips, mouth, tongue, or throat
- Trouble swallowing or throat tightness
- Itching, skin rash, or pale red bumps on the skin called hives
- Nausea or vomiting
- Dizziness, feeling lightheaded, or fainting
- Stomach cramps
- Joint pain
Low Blood Pressure (Hypotension). Tizanidine may cause low blood pressure. If you feel faint or dizzy, lie down. Tell your healthcare provider right away if you have any of the following symptoms of low blood pressure.
- Dizziness, feeling lightheaded, or fainting
- Confusion
- Feeling weak or tired
Dizziness and Sleepiness. Tizanidine can make you dizzy or sleepy. Do not drive or do other activities that require alertness or coordination until you know how tizanidine affects you.
Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking tizanidine. Keep all appointments for blood work so your healthcare provider can check your liver function while you are taking tizanidine. Call your healthcare provider right away if you have any of the following symptoms of liver damage.
- Nausea or vomiting
- Stomach or belly pain
- Fever
- Weakness or unusual tiredness
- Itching
- Loss of appetite
- Light-colored poop
- Dark-colored urine (pee)
- Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
Hallucinations. Tizanidine may cause hallucinations. Call your healthcare provider right away if you experience any symptoms of hallucinations. These can include seeing, smelling, or hearing things that are not really there.
Warnings & Precautions
Who should not use tizanidine?
Allergies to Ingredients. People who are allergic to any of the following should not take tizanidine.
- Tizanidine
- Zanaflex
- Any of the ingredients in the specific product dispensed
Your pharmacist can tell you all of the ingredients in the specific tizanidine products they stock
Drug Interactions. Tizanidine should not be taken while you are using certain other medicines. Before taking tizanidine, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.
What should I know about tizanidine before using it?
Do not take tizanidine unless it has been prescribed to you by a healthcare provider. Take it as prescribed. Taking more than prescribed can increase your risk for side effects.
The effects of tizanidine do not last long. Because of this, you should reserve taking tizanidine for those daily activities and times when relief of spasticity is most important to you.
Do not share tizanidine with other people, even if they have the same condition as you. It may harm them.
Keep tizanidine out of the reach of children.
Do not stop taking tizanidine without talking to your healthcare provider. Stopping tizanidine suddenly can cause a sudden increase in blood pressure, fast heartbeat, and stiff muscle tone. If you need to stop taking tizanidine, your healthcare provider will give you instructions on how to stop the medicine.
Tizanidine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how tizanidine affects you.
People who are ages 65 years and older can be at greater risk for some side effects from tizanidine. Talk to your healthcare provider about your risks if you are 65 years and older.
Do not switch between tizanidine tablets and capsules. This can affect how well tizanidine manages your muscle spasms.
What should I tell my healthcare provider before using tizanidine?
Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if tizanidine is right for you.
In particular, make sure that you discuss any of the following.
Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.
- Liver problems
- Kidney problems
- Low blood pressure (hypotension)
Pregnancy. It is not known if or how tizanidine could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.
Breastfeeding. It is not known if tizanidine passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take tizanidine while breastfeeding.
Interactions
Does tizanidine interact with foods or drinks?
Take tizanidine consistently either with or without food. Once a decision is made to take tizanidine with or without food, avoid changing how it is given. This is because changes will affect how well the medicine works.
Alcohol can increase the amount of tizanidine in your blood. The risk of drowsiness and dizziness may also be increased if you drink alcohol while taking tizanidine.
Does tizanidine interact with other medicines (drug interactions)?
Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.
In particular, make sure that you discuss if you are using any of the following before taking tizanidine.
- Ciprofloxacin (Cipro), a medicine used for bacterial infections
- Fluvoxamine (Luvox), a medicine used for certain mental health conditions
- Other alpha-2 agonist medicines, such as clonidine (Catapres and others) and guanfacine (Intuniv), which are used for high blood pressure and other conditions
- Any other medicine that causes dizziness and sleepiness, such as prescription pain medicines, sleep medicines, and medicines for anxiety
- A birth control pill
Some other medicines may alter the blood levels of tizanidine. Tell your healthcare provider about all medicines that you take or have recently taken.
This may not be a complete list of medicines that can interact with tizanidine. Always check with your healthcare provider.
Overdose/Missed Dose
What should I do if I accidentally use too much tizanidine?
If you or someone else has used too much tizanidine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.
What should I do if I miss a dose of tizanidine?
Tizanidine is meant to be taken only when needed. Take it as your healthcare provider recommends. If you are unsure how to handle a missed dose, ask your pharmacist or other healthcare provider. Do not take double or extra doses.
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