Generic name: tizanidine (tye ZAN i deen)
Brand name: Zanaflex
Drug class: Skeletal muscle relaxants
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 not listed in this medication guide.
Tizanidine is a short-acting medication that should be taken only for daily activities that require relief from muscle spasticity.
You should not take tizanidine if you are also taking fluvoxamine (Luvox) or ciprofloxacin (Cipro).
Do not use tizanidine at a time when you need muscle tone for safe balance and movement during certain activities. In some situations, it may endanger your physical safety to be in a state of reduced muscle tone.
Switching between 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 medicine 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.
Avoid drinking alcohol. It can increase some of the side effects of this medicine.
Before taking this medicine
You should not use tizanidine if you are allergic to it, or if:
- you also take the antidepressant fluvoxamine (Luvox); or
- you also take the antibiotic ciprofloxacin (Cipro).
To make sure tizanidine is safe for you, tell your doctor if you have ever had:
- liver disease;
- kidney disease; or
- low blood pressure.
It is not known whether tizanidine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.
It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.
How should I take tizanidine?
Take tizanidine exactly as it was prescribed for you. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.
Tizanidine is usually taken up to 3 times in one day. Allow 6 to 8 hours to pass between doses. Do not take more than three doses (36 mg) in a 24-hour period. Too much of this medicine can damage your liver.
You may take tizanidine with or without food, but take it the same way each time. Switching between taking with food and taking it without food can make the medicine less effective or cause increased side effects.
Switching between tablets and capsules may cause changes in side effects or how well the medicine works.
- Taking the tablets with food can increase your blood levels of tizanidine.
- Taking the capsules with food can decrease your blood levels of tizanidine.
If you make any changes in how you take tizanidine, tell your doctor if you notice any change in side effects or in how well the medicine works.
Tizanidine is a short-acting medication, and its effects will be most noticeable between 1 and 3 hours after you take it. You should take this medicine only for daily activities that require relief from muscle spasms.
You will need frequent blood tests to check your liver function.
If you stop using this medicine suddenly after long-term use, you may have withdrawal symptoms such as dizziness, fast heartbeats, tremors, and anxiety. Ask your doctor how to safely stop using this medicine.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include weakness, drowsiness, confusion, slow heart rate, shallow breathing, feeling light-headed, or fainting.
What to avoid
Do not use tizanidine at a time when you need muscle tone for safe balance and movement during certain activities. In some situations, it may be dangerous for you to have reduced muscle tone.
Drinking alcohol with this medicine can cause side effects.
Avoid driving or hazardous activity until you know how this medicine will affect you. Your reactions could be impaired. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.
Tizanidine side effects
Get emergency medical help if you have signs of an allergic reaction to tizanidine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
- a light-headed feeling, like you might pass out;
- weak or shallow breathing;
- confusion, hallucinations; or
- pain or burning when you urinate.
Common tizanidine side effects may include:
- drowsiness, dizziness, weakness;
- feeling nervous;
- blurred vision;
- flu-like symptoms;
- dry mouth, trouble speaking;
- abnormal liver function tests;
- runny nose, sore throat;
- urination problems, painful urination;
- vomiting, constipation; or
- uncontrolled muscle movements.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect tizanidine?
Taking tizanidine with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.
Tell your doctor about all your other medicines, especially:
- birth control pills;
- an antibiotic - ciprofloxacin, levofloxacin, moxifloxacin, or ofloxacin;
- blood pressure medicine - clonidine, guanfacine, methyldopa;
- heart rhythm medicine - amiodarone, mexiletine, propafenone, verapamil; or
- stomach acid medicine - cimetidine, famotidine.
This list is not complete. Other drugs may interact with tizanidine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.