Zanaflex (Tizanidine) - Oral

What Is Zanaflex?

Zanaflex (tizanidine) is a prescription muscle relaxant used to treat extreme muscle tightness (spasticity). Muscle spasticity can occur due to different medical problems, like stroke, that affect the nervous system.

Zanaflex belongs to a group of drugs called central alpha-2 adrenergic agonists. These drugs block a signaling receptor found on some neurons inside the spinal cord. Ultimately this leads to decreased activation of the neurons that usually trigger muscle contraction.

Zanaflex is an oral medication available as tablets or capsules.

Drug Facts

Generic Name: Tizanidine

Brand Name(s): Zanaflex

Administration Route(s): Oral

Drug Availability: Prescription

Therapeutic Classification: Skeletal muscle relaxant

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Tizanidine

Dosage Form(s): Tablet, capsule

What Is Zanaflex Used For?

The Food and Drug Administration (FDA) approved Zanaflex to treat muscle spasticity caused by medical conditions that affect the brain or spinal cord. Some of the conditions that can cause muscle spasticity include:

How to Take Zanaflex

You can take Zanaflex either with or without food. However, you should take it the same way each time: either on a relatively empty stomach or with food. This is because food has a significant impact on how the drug breaks down in the body. Switching how you take Zanaflex each time can make it harder to ensure you're getting the right dose and affect the efficacy of the medication and how your body reacts to it.

Usually, people start on a dosage of 2 milligrams (mg), with repeat doses every six to eight hours as needed. Your healthcare provider may gradually increase your dose until your symptoms are managed. Because Zanaflex works for a relatively short period (several hours), you’ll want to time your dose when you most need relief from muscle tightness. For example, you may want to take it about an hour before you plan to perform your physical activities.

Storage

Store Zanaflex at room temperature, safely away from pets and children.

Off-Label Uses

Zanaflex has been used off-label to treat some other medical conditions as well. The drug hasn’t gone through the full set of medical studies to be approved by the FDA for these conditions.

Some examples are:

Some evidence shows that the drug might be helpful in these cases. However, it’s not clear if Zanaflex is truly effective for these conditions.

Zanaflex has only been approved for adults. However, sometimes healthcare providers prescribe it to children as well. This is also technically an off-label use.

How Long Does Zanaflex Take to Work?

Zanaflex usually starts to work within an hour to relieve your symptoms. However, you might not be getting full relief when you first start taking Zanaflex. Your healthcare provider may need to gradually increase your dose to find what works for you.

What Are the Side Effects of Zanaflex?

You might not notice any side effects from using Zanaflex. However, it’s good to have an idea of what you might expect. You may be more likely to have side effects if you are taking a higher dose.

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

Some of the more common possible side effects of Zanaflex are:

Some of these may decrease with time. For example, you might notice a lot of sleepiness when you first start taking the medication or increasing your dose. But as your body adjusts to the medicine, it may not be as much a problem.

Severe Side Effects

Some potential serious side effects include:

For potentially serious side effects like these, you might need to stop taking Zanaflex. But do this while working with your healthcare provider. If you have side effects that you think may be serious, call your healthcare provider right away. Call 911 if you think you are having a medical emergency, like difficulty breathing.

Other potentially serious problems can happen if you stop taking the medicine abruptly, especially if you’ve been on a relatively high dose. Suddenly discontinuing Zanaflex can cause problems like:

Report Side Effects

Zanaflex may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Zanaflex Should I Take?

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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.

Modifications

If you are taking the capsule form of Zanaflex, you can sprinkle the contents on food. For the tablet form, you can cut or crush the tablet if needed.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is very close to your next dose, don’t double up. If you skip a dose, you might notice that your muscles are tighter than usual.

Overdose: What Happens If I Take Too Much Zanaflex?

It probably won't be a big deal if you accidentally take a single extra dose of Zanaflex. However, it’s worth checking in with a healthcare provider anyway. People who take a lot of extra Zanaflex might have serious health complications, including heart, kidney, and liver damage.

Overdose symptoms might include sleepiness, dizziness, weakness, and confusion.

What Happens If I Overdose on Zanaflex?

If you think you or someone else may have overdosed on Zanaflex, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Zanaflex, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

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.

What Are Reasons I Shouldn’t Take Zanaflex?

You shouldn't use Zanaflex if you know you are allergic to it.

Zanaflex hasn’t been well studied in pregnancy. People who are pregnant or breastfeeding should only use Zanaflex if the benefits outweigh the risks in their particular situation.

People with kidney problems need to be cautious using Zanaflex. You may still be able to use Zanaflex, but you may need to use a lower dose. Otherwise, you could be at a greater risk of side effects.

Zanaflex has also not been well studied in people over 65. Some of these people may be at greater risk of side effects from Zanaflex.

What Other Medications Interact With Zanaflex?

Some medications should never be taken if you are using Zanaflex. In other cases, you may be able to use the other medication, but you may need to proceed cautiously. That’s because of drug interactions—how a certain drug affects how another is broken down in the body.

Zanaflex should never be taken with drugs that strongly affect a specific group of liver enzymes (called CYP1A2). Important examples are:

  • Antibiotic Cipro (ciprofloxacin)
  • Antidepressant Luvox (fluvoxamine)

Other drugs that affect this group of enzymes may be used, but only cautiously and with careful monitoring. These include:

  • Certain antiarrhythmic drugs like Pacerone (amiodarone)
  • Certain drugs for acid reflux like Tagamet (cimetidine)
  • Some antiviral drugs like Zovirax (acyclovir)
  • Oral contraceptives

Because Zanaflex can be sedating, you’ll also need to limit your use of other drugs that can have similar, cumulative effects. For example, you may need to avoid or limit:

  • Alcohol
  • Benzodiazepine drugs like Valium (diazepam)
  • Opioid drugs like OxyContin (oxycodone)

To be safe, talk to your healthcare provider about all of your medications, including over-the-counter and herbal products.

What Medications Are Similar?

If you need to take medications for spasticity from a medical condition, some other potential options are:

  • Lioresal (baclofen)
  • Catapres, Kapvay (clonidine)
  • Benzodiazepine drugs like Valium (diazepam)

Baclofen is a very effective treatment. It is often the one that is tried first to treat spasticity. You can take it orally or through a pump that delivers the medication directly into the area around the spinal cord.

Another option, clonidine, has a very similar chemical structure to Zanaflex. Clonidine is available under brand names, such as Catapres and Kapvay. Clonidine works for a more extended period compared with Zanaflex. Therefore, using Zanaflex may give you greater flexibility. Clonidine may also pose more risk of lowering your blood pressure too much.

Drugs like Valium can be helpful for some people, but they can cause drowsiness and drug dependence. Therefore, they might not be the best choice to take long term.

One advantage of Zanaflex is that it tends to cause fewer problems with muscle weakness than these other drugs. Zanaflex can be used alone, but it is often prescribed along with other drugs, like baclofen, to treat spasticity. However, it’s important to be thoughtful about how they are combined to limit your risk of side effects. Your healthcare provider will help you work out a safe and effective regimen. 

Frequently Asked Questions

  • What is Zanaflex used for?

    Zanaflex is used to treat medical conditions that cause muscle spasticity (extreme muscle tightness) that can happen in spinal cord injuries, multiple sclerosis, stroke, and some other health conditions. It is also sometimes used off-label to treat conditions like back pain, but it’s not clear how effective it is.

  • Will Zanaflex make me sleepy?

    Sleepiness is a relatively common side effect of Zanaflex. However, this is also true of most other drugs used to treat muscle spasticity. Usually, this problem is most severe when you first start taking the drug. Then, after using it for a while, your body may adapt.

  • How long does it take for Zanaflex to work?

    Zanaflex takes an hour or so to kick in. It may stop working four to five hours after. It can be helpful to time your dose around the activities you plan to do that day.

  • Should I take Zanaflex with food?

    You can take Zanaflex with or without food. However, you should take it the same way each time. That’s because the drug is broken down at different rates when you take it with food. By taking it in a consistent way, you’ll have a better idea of what to expect from your dose.

  • How can I stop taking Zanaflex?

    If you want to stop taking Zanaflex, talk to your healthcare provider. You shouldn’t suddenly discontinue your medication, as it can cause uncomfortable and dangerous side effects.

    If you and your healthcare provider decide that stopping Zanaflex is the right move, you’ll slowly lower your dose. This will minimize any chance of side effects.

How Can I Stay Healthy While Taking Zanaflex?

If you need to take Zanaflex for muscle spasticity, you may be dealing with multiple challenging medical problems. Fortunately, medications like Zanaflex can help improve your quality of life.

Like every medication, Zanaflex has its risks and possible side effects. But you can minimize these by staying in close contact with your healthcare provider, monitoring for potential issues, and taking your medication as prescribed.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

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