- What is Zanaflex?
- Important information
- Before taking this medicine
- How should I take Zanaflex?
- What happens if I miss a dose?
- What happens if I overdose?
- What should I avoid while taking Zanaflex?
- Zanaflex side effects
- Zanaflex dosing information
- What other drugs will affect Zanaflex?
- Further information
- More about Zanaflex (tizanidine)
- About tizanidine
- Before taking tizanidine
- How to take tizanidine
- Getting the most from your treatment
- Can tizanidine cause problems?
- How to store tizanidine
- Important information about all medicines
Generic Name: tizanidine (tye ZAN i deen)
Brand Names: Zanaflex
Medically reviewed by Kaci Durbin, MD Last updated on Mar 12, 2019.
- Side Effects
What is Zanaflex?
Zanaflex (tizanidine) is a short-acting muscle relaxer. It works by blocking nerve impulses (pain sensations) that are sent to your brain.
Zanaflex is used to treat spasticity associated with diseases like multiple sclerosis and spinal cord injuries by temporarily relaxing muscle tone.
Zanaflex may also be used for purposes not listed in this medication guide.
Zanaflex 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 Zanaflex 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 Zanaflex 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 Zanaflex, 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 tizanidine 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 Zanaflex.
Avoid drinking alcohol. It can increase some of the side effects of tizanidine.
Before taking this medicine
You should not use Zanaflex if you are allergic to tizanidine, or if:
you also take the antidepressant fluvoxamine (Luvox); or
you also take the antibiotic ciprofloxacin (Cipro).
To make sure Zanaflex is safe for you, tell your doctor if you have:
kidney disease; or
low blood pressure; or
high blood pressure.
It is not known whether Zanaflex will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.
It is not known whether tizanidine passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
How should I take Zanaflex?
Take Zanaflex 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.
In most cases you may take Zanaflex up to 3 times in one day if needed. Allow 6 to 8 hours to pass between doses.
You may take Zanaflex with or without food, but take it the same way each time. Switching between taking tizanidine with food and taking it without food can make the medicine less effective or cause increased side effects.
Switching between Zanaflex tablets and capsules can also cause changes in side effects or how well the medicine works.
Follow your doctor’s instructions carefully. After making any changes in how you take Zanaflex, contact your doctor if you notice any change in side effects or in how well the medicine works.
Zanaflex 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.
Do not take more than three doses (36 mg) in a 24-hour period. Too much of this medicine can damage your liver.
You will need frequent blood tests to check your liver function.
If you stop using Zanaflex 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 should I avoid while taking Zanaflex?
Do not use Zanaflex 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.
This medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.
Zanaflex side effects
Get emergency medical help if you have signs of an allergic reaction to Zanaflex: 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
yellowing of the eyes or skin.
pain or burning when you urinate.
Common Zanaflex side effects may include:
drowsiness, dizziness, weakness;
abnormal liver function tests;
runny nose, sore throat;
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.
Zanaflex dosing information
Usual Adult Dose for Muscle Spasm:
-Initial dose: 2 mg orally every 6 to 8 hours as needed
-The dose of Zanaflex can be increased by your doctor if needed
-The medication effects peak in about 1 to 2 hours and last for 3 to 6 hours
-Do not take more than 16mg of Zanaflex at one time. Do not take more than 36mg in 24 hours.
-The capsules and tablets are absorbed differently by the body. Do not switch from one to the other without talking to your doctor.
-Zanaflex should be taken with food every time or without food every time. Do not switch back and forth.
What other drugs will affect Zanaflex?
Taking Zanaflex with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before taking a sleeping pill, narcotic pain medicine, prescription cough medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.
Tell your doctor about all your current medicines and any you start or stop using, especially:
birth control pills;
an antibiotic, including ciprofloxacin, gemifloxacin, levofloxacin, moxifloxacin, ofloxacin, or others;
blood pressure medicine such as clonidine, guanfacine, methyldopa;
heart rhythm medicine including amiodarone, mexiletine, propafenone, verapamil; or
stomach acid medicine such as 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.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Zanaflex only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2020 Cerner Multum, Inc. Version: 3.01.
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Tizanidine is a short-acting muscle relaxer that’s marketed under the brand name Zanaflex.
It’s used to treat muscle spasms caused by certain conditions such as multiple sclerosis, ALS, or spinal cord injury.
It is also prescribed off-label for certain headache disorders, symptoms of fibromyalgia, and as a sleep aid.
Tizanidine works by blocking nerve impulses that are sent to your brain. If you are suffering from spasms, cramping, and tightness of the muscles, your doctor may prescribe tizanidine.
Tizanidine does not cure these problems, but it may allow other treatment, such as physical therapy, to be more helpful in improving your condition.
Tizanidine is a short-acting medication that you should only take for daily activities that require relief from muscle spasms.
Using too much tizanidine can severely damage your liver, causing liver failure.
Tell your doctor if you have any type of previous injury to your liver. Your doctor will likely check blood levels after a month of use if you fall into this category.
It’s also important to inform your doctor if you have experienced kidney failure.
Call your doctor immediately if you develop dry mouth, dizziness, a strong desire for sleep, or any sign of weakness while taking tizanidine. Your dosage may have to be reduced or discontinued.
You should not drive, use heavy machinery, or do any activity that requires you to be alert while using tizanidine.
If you are scheduled for surgery, let your doctor know you are taking tizanidine.
Before having surgery, tell your doctor or dentist about all the products you use, including over-the-counter (OTC) drugs.
In older adults, the effects of tizanidine may also last much longer.
Pregnancy and Tizanidine
Tizanidine may be harmful to an unborn baby.
Animal studies have shown an adverse effect, but there are no adequate studies in pregnant women. Tell your doctor if you are pregnant or might become pregnant during treatment.
Do not use this medication without telling your doctor if you are breastfeeding.
Tizanidine ‘High’ and Recreational Use
Because of tizanidine’s sedative effects, numerous online and anecdotal reports have suggested that some people abuse the drug for a narcotic-like “high.”
However, tizanidine is not a narcotic.
Take tizandine only as directed by your doctor, and keep this and all other drugs away from children, teenagers, and anyone for whom the drug has not been prescribed.
|Type of medicine||A muscle relaxant|
|Used for||Muscle spasticity in adults|
Tizanidine belongs to a group of medicines called muscle relaxants. Muscle relaxants are medicines that are used to prevent or reduce muscle spasms and spasticity. Spasticity occurs when muscles contract tightly and become stiff and harder to use. It often causes pain and discomfort.
Tizanidine is used to relieve spasticity which results from long-term conditions such as multiple sclerosis and following long-term injuries to the head or back. It works on the nerves in your brain and spine to help relax affected muscles.
Before taking tizanidine
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking tizanidine it is important that your doctor knows:
- If you have any problems with the way your liver works, or any problems with the way your kidneys work.
- If you are pregnant or breastfeeding.
- If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine.
How to take tizanidine
- Before you start the treatment, read the manufacturer’s printed information leaflet from inside the pack. It will give you more information about tizanidine and will provide you with a full list of the side-effects which you may experience from taking it.
- When starting the treatment, your doctor will give you a small dose (usually 2 mg once daily) and will then gradually increase your dose at 3- to 4-day intervals. This allows your doctor to make sure that you have the dose that helps your condition but avoids any unwanted symptoms. Tizanidine tablets have a relatively short time of action, so you will be prescribed several doses to take each day once you are on a maintenance dose.
- Swallow the tablet with a drink of water. You can take tizanidine either before or after meals.
- Continue to take tizanidine exactly as your doctor tells you to. Your dose will be printed on the label of the pack to remind you about what your doctor said to you. Once you are established on a regular dose of tizanidine, try to take your doses at the same times of day each day, as this will help you to remember to take them.
- If you do forget to take a dose, take it when you remember unless your next dose is about due. If it is nearly time for your next dose then take the next dose when it is due but leave out the forgotten dose. Do not take two doses together to make up for a missed dose.
Getting the most from your treatment
- Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. You will need to have some blood tests from time to time to check that your liver is working properly.
- Tizanidine can cause drowsiness and may affect your reactions. Be careful this does not put you at risk if you are using any tools or machines, or if you drive.
- It is recommended that you do not drink alcohol while you are on tizanidine. This is because the risk of side-effects, such as feeling sleepy and dizzy, is increased.
- Continue to take the tablets unless your doctor tells you otherwise – treatment with tizanidine is usually long-term. Suddenly stopping treatment can cause problems, so your doctor will want you to reduce your dose gradually if this becomes necessary.
- If you are due to have an operation or dental treatment, please tell the person carrying out the treatment which medicines you are taking.
Can tizanidine cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with tizanidine. You will find a full list in the manufacturer’s information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
|Very common tizanidine side-effects (these affect more than 1 in 10 people)||What can I do if I experience this?|
|Feeling drowsy, dizzy, tired, or weak||If this happens, do not drive and do not use tools or machines. Do not drink alcohol|
|Dry mouth||Try chewing sugar-free gum or sucking sugar-free sweets|
|Feeling sick, upset stomach||Eat simple meals – avoid rich or spicy foods|
|Common tizanidine side-effects (these affect less than 1 in 10 people)||What can I do if I experience this?|
|Feeling light-headed, especially when you stand up (due to low blood pressure)||Moving more slowly may help|
|Difficulty sleeping||If troublesome, speak with your doctor|
Important: a few people have developed problems with their liver whilst taking tizanidine. Although your doctor will check for this, you should speak with your doctor as soon as possible if you have any unexplained sickness, loss of weight, or feel extremely tired.
If you experience any other symptoms which you think may be due to the tablets, please speak with your doctor or pharmacist for further advice.
How to store tizanidine
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
This medicine is for you. Do not give it to other people even if their condition appears to be the same as yours.
If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Aripiprazole Lauroxil
- Arsenic Trioxide
- Estradiol Valerate
- Ethinyl Estradiol
- Ethynodiol Diacetate
- Glycopyrronium Tosylate
- Inotuzumab Ozogamicin
- Morphine Sulfate Liposome
- Peginterferon Alfa-2b
- Secretin Human
- Sodium Phosphate
- Sodium Phosphate, Dibasic
- Sodium Phosphate, Monobasic
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.