Generic name: tizanidine [ tye-ZAN-i-deen ]
Drug class: Skeletal muscle relaxants

Medically reviewed by Kaci Durbin, MD. Last updated on Apr 8, 2021.

What is Zanaflex?

Zanaflex 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.

Warnings

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 ever had:

• liver disease;

• 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 may not be safe to breastfeed while using tizanidine. Ask your doctor about any risk.

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.

Zanaflex 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 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 may cause changes in side effects or how well the medicine works.

If you make any changes in how you take Zanaflex, tell 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.

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 medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

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 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.

Avoid driving or hazardous activity until you know how Zanaflex will affect you. Your reactions could be impaired. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

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;

• dry mouth;

• feeling nervous;

• blurred vision;

• flu-like symptoms;

• 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.

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.

Comments:
-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 using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Tell your doctor about all your other medicines, especially:

• acyclovir;

• ticlopidine;

• zileuton;

• birth control pills;

• an antibiotic, including ciprofloxacin, 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.

Where can I get more information?

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.

Popular FAQ

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

Copyright 1996-2023 Cerner Multum, Inc. Version: 4.01.

Generic name: tizanidine (oral route) [ tye-ZAN-i-deen ]
Drug class: Skeletal muscle relaxants

Medically reviewed by Drugs.com. Last updated on Jan 8, 2023.

Commonly used brand name(s)

In the U.S.

• Comfort Pac w/Tizanidine
• Zanaflex
• Zanaflex Capsule

Available Dosage Forms:

• Tablet
• Capsule

Therapeutic Class: Skeletal Muscle Relaxant, Centrally Acting

Uses for Zanaflex Capsule

Tizanidine is used to help relax certain muscles in your body. It relieves spasms, cramping, and tightness of the muscles caused by medical problems, such as multiple sclerosis or certain injuries to the spine. 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 acts on the central nervous system (CNS) to produce its muscle relaxant effects. Its actions on the CNS may also cause some of the medicine''s side effects.

This medicine is available only with your doctor''s prescription.

Before using Zanaflex Capsule

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of tizanidine in the pediatric population. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatrics-specific problems that would limit the usefulness of tizanidine in the elderly. However, elderly patients are more likely to have kidney problems, which may require caution in patients receiving this medicine.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with medicines

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.

• Ciprofloxacin
• Fluvoxamine
• Potassium Citrate
• Viloxazine

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.

• Adagrasib
• Alfentanil
• Alprazolam
• Benzhydrocodone
• Bromazepam
• Buprenorphine
• Butorphanol
• Calcium Oxybate
• Cannabidiol
• Capmatinib
• Cetirizine
• Cimetidine
• Citalopram
• Clonazepam
• Clozapine
• Codeine
• Daridorexant
• Deferasirox
• Desogestrel
• Dexmedetomidine
• Dienogest
• Dihydrocodeine
• Doxylamine
• Drospirenone
• Esketamine
• Estradiol Valerate
• Ethinyl Estradiol
• Ethynodiol Diacetate
• Famotidine
• Fentanyl
• Fexinidazole
• Flibanserin
• Gabapentin
• Gabapentin Enacarbil
• Gestodene
• Givosiran
• Glucagon
• Glycopyrrolate
• Glycopyrronium Tosylate
• Hydrocodone
• Hydromorphone
• Ketamine
• Lemborexant
• Levocetirizine
• Levonorgestrel
• Levorphanol
• Lofexidine
• Loxapine
• Magnesium Oxybate
• Meperidine
• Mestranol
• Methacholine
• Methadone
• Metoclopramide
• Mexiletine
• Midazolam
• Mobocertinib
• Morphine
• Morphine Sulfate Liposome
• Nalbuphine
• Norethindrone
• Norfloxacin
• Norgestimate
• Norgestrel
• Ofloxacin
• Oxycodone
• Oxymorphone
• Pacritinib
• Peginterferon Alfa-2b
• Pentazocine
• Periciazine
• Pixantrone
• Ponesimod
• Potassium Oxybate
• Pregabalin
• Propafenone
• Quetiapine
• Remifentanil
• Remimazolam
• Revefenacin
• Rofecoxib
• Ropeginterferon Alfa-2b-njft
• Scopolamine
• Secretin Human
• Sodium Oxybate
• Sufentanil
• Tacrolimus
• Tapentadol
• Taurursodiol
• Ticlopidine
• Tiotropium
• Tramadol
• Trazodone
• Vemurafenib
• Verapamil
• Voclosporin
• Zileuton
• Zolpidem

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.

• Fosphenytoin
• Lisinopril
• Phenytoin

Interactions with food/tobacco/alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. 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 is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

• Tobacco

Other medical problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Kidney disease or
• Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper use of Zanaflex Capsule

This section provides information on the proper use of a number of products that contain tizanidine. It may not be specific to Zanaflex Capsule. Please read with care.

Take this medicine only as directed by your doctor. Do not take more of it and do not take it more often than your doctor ordered. To do so may increase the chance of side effects.

When you take the different dosage forms (tablets, capsules, capsule contents sprinkled over applesauce) of tizanidine with food, it affects the amount of the medicine absorbed into your blood differently. Follow your doctor''s instructions for when to take this medicine and whether or not you should take it with food.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor''s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage forms (capsules or tablets):
  • For muscle relaxation:
    • Adults—At first, 2 milligrams (mg) every 6 to 8 hours. Your doctor may adjust your dose as needed. Do not take more than 36 mg within a 24-hour period.
    • Children—Use and dose must be determined by your doctor.

Missed dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using Zanaflex Capsule

It is important that your doctor check your progress at regular visits, especially during the first few weeks of treatment with this medicine. This will allow your doctor to see if the medicine is working properly and to check for unwanted effects. Blood tests may be needed to check for unwanted effects.

Do not use this medicine together with ciprofloxacin or fluvoxamine. Using these medicines together may cause serious unwanted effects.

Dizziness, lightheadedness, or fainting may occur when you get up suddenly from a lying or sitting position. Getting up slowly may help lessen this problem.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds, sedatives, tranquilizers, or sleeping medicine, prescription pain medicine or narcotics, barbiturates, medicine for seizures, other muscle relaxants, or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using tizanidine.

This medicine may cause dizziness, drowsiness, lightheadedness, clumsiness or unsteadiness, or vision problems in some people. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert, well-coordinated, and able to see well.

Hallucinations (visual) may occur while you are using this medicine. Check with your doctor right away if you have hallucinations (seeing things that are not there).

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

Do not suddenly stop taking this medicine without checking first with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping completely. This may help prevent a possible worsening of your condition and reduce the possibility of withdrawal symptoms.

Tizanidine may cause dryness of the mouth. For temporary relief, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if dry mouth continues for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Zanaflex Capsule side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

• Chest pain or discomfort
• fever or chills
• nausea or vomiting
• nervousness
• pain or burning while urinating
• unusual tiredness

Less common

• Blurred vision
• flu-like symptoms
• irregular heartbeat
• itching skin
• kidney stones
• right upper stomach tenderness
• seeing things that are not there
• shortness of breath
• weight gain

Incidence not known

• Continuing vomiting
• general feeling of tiredness or weakness
• headache
• light-colored stools

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

• Blurred vision
• change in consciousness
• chest pain or discomfort
• confusion
• decreased awareness or responsiveness
• difficult or troubled breathing
• dizziness, faintness or lightheadedness when getting up from a lying position
• irregular, fast or slow, or shallow breathing
• lightheadedness, dizziness, or fainting
• loss of consciousness
• pale or blue lips, fingernails, or skin
• severe sleepiness
• sleepiness or unusual drowsiness
• slow or irregular heartbeat
• sweating
• unusual tiredness or weakness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Dizziness or lightheadedness, especially when getting up from a lying or sitting position
• drowsiness
• dry mouth
• fatigue
• sleepiness
• weakness

Less common

• Constipation
• nervousness
• sore throat

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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

Frequently asked questions

• What is Miderizone used for?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer