- Low blood pressure warning: Tizanidine can cause very low blood pressure that leads to dizziness or fainting. To help reduce this risk, your doctor may prescribe the lowest dose of this drug that works for you. If you already take medications that lower blood pressure, your doctor may check your blood pressure more often.
- Liver damage warning: Tizanidine can cause liver damage. If you have liver disease, talk with your doctor about whether this drug is safe for you. If you take this drug, your doctor may monitor you for changes in how well your liver works.
- Hallucinations or delusions warning: Tizanidine can cause visual hallucinations (seeing things that aren’t real). It can also cause delusions (believing things that aren’t real). If have either of these side effects, stop taking this drug and call your doctor right away.
Tizanidine oral tablet is a prescription drug that’s available as a brand-name drug Zanaflex. It’s also available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version. This drug also comes in an oral capsule.
Why it's used
Tizanidine is used to manage muscle spasms. Symptoms can include muscle tightness, pain, or stiffness. This drug is often used for people with multiple sclerosis, spinal cord injury, or muscle spasticity.
How it works
Tizanidine belongs to a class of drugs called alpha-2-adrenergic agonists. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.
Tizanidine reduces the activity of nerves in the spinal cord that control muscles. This helps to reduce muscle spasms.
Tizanidine oral tablet may cause drowsiness. It may also cause other side effects.
More common side effects
The more common side effects of tizanidine can include:
- dry mouth
- urinary tract infection
- trouble speaking
- runny nose
- sore throat
- vision problems
If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.
Serious side effects
Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:
- Hallucinations. Symptoms can include:
- seeing things that aren’t real
- Delusions. Symptoms can include:
- believing things that aren’t real
- Extremely low blood pressure. Symptoms can include:
- dizziness or lightheadedness, especially when standing after sitting or lying down
- Liver damage. Symptoms can include:
- increased bleeding or bruising
- yellowing of your skin or the whites of your eyes
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
Tizanidine oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.
To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.
Drugs that should not be used with tizanidine
Do not take these drugs with tizanidine. When used with tizanidine, these drugs can cause dangerous effects in the body. Examples of these drugs include:
- Fluvoxamine and ciprofloxacin. Using these drugs with tizanidine may cause very low blood pressure. It may also cause increased drowsiness or decreased muscle control.
- Other alpha-2 agonist medications such as clonidine, methyldopa, guanfacine, or guanabenz. Using these drugs with tizanidine can cause very low blood pressure.
Drugs that increase the risk of side effects from tizanidine
Taking tizanidine with certain medications raises your risk of side effects from tizanidine. This is because the amount of tizanidine in your body is increased. Examples of these drugs include:
- Zileuton. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Certain antibiotics called fluoroquinolones (other than ciprofloxacin), such as levofloxacin, moxifloxacin, or gemifloxacin. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Certain heart rhythm drugs such as amiodarone, mexiletine, propafenone, or verapamil. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Antacids such as cimetidine or famotidine. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Oral contraceptives. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness. It’s not recommended to use oral contraceptives with tizanidine. If these drugs must be used together, your doctor may prescribe a single tizanidine dose of 2 mg. They may then slowly increase the dose by 2–4 mg per day.
- Acyclovir. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Ticlopidine. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Benzodiazepines such as alprazolam, lorazepam, or diazepam. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Opioids such as morphine, methadone, or oxycodone. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
- Certain antidepressants such as amitriptyline, nortriptyline, or protriptyline. Increased side effects can include decreased blood pressure, decreased heart rate, or extreme drowsiness.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Tizanidine oral tablet comes with several warnings.
Tizanidine can cause a severe allergic reaction. Symptoms can include:
- trouble breathing
- swelling of your throat or tongue
If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 911 or go to the nearest emergency room.
Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).
The use of drinks that contain alcohol increases the amount of tizanidine in your body. This can cause increased side effects from tizanidine.
Warnings for people with certain health conditions
For people with decreased liver function: Talk with your doctor about whether tizanidine is safe for you. If you take this drug, your doctor may give you a lower dose. Also, your doctor should check your liver function at the start of treatment. They may check it again one month after your maximum dose has been prescribed.
For people with decreased kidney function: Talk with your doctor about whether tizanidine is safe for you. If you take this drug, your doctor may give you a lower dose. Also, your doctor will watch for buildup of too much tizanidine in your body. Symptoms can include dry mouth, dizziness, or drowsiness.
Warnings for other groups
For pregnant women: Tizanidine is a category C pregnancy drug. That means two things:
- Research in animals has shown adverse effects to the fetus when the mother takes the drug.
- There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.
Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should only be used if the potential benefit justifies the potential risk to the fetus. Call your doctor if you become pregnant while taking this drug.
For women who are breastfeeding: It’s not known if tizanidine passes into breast milk and causes side effects in a child who is breastfed. Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.
For seniors: The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.
For children: This medication has not been studied in children. It should not be used in people younger than 18 years.
This dosage information is for tizanidine oral tablet. All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:
- your age
- the condition being treated
- how severe your condition is
- other medical conditions you have
- how you react to the first dose
Forms and strengths
- Form: Oral tablet
- Strengths: 2 mg, 4 mg
- Form: Oral capsule
- Strengths: 2 mg, 4 mg, 6 mg
- Form: Oral tablet
- Strengths: 4 mg
- Form: Oral capsule
- Strengths: 2 mg, 4 mg, 6 mg
Dosage for muscle spasms
Adult dosage (ages 18 years and older)
- Typical starting dosage: 2 mg every 6–8 hours as needed.
- Dosage increases: Your doctor may increase your dosage by 2–4 mg until your symptoms are controlled. They will wait 1–4 days between any increases.
- Maximum dosage: 3 doses in 24 hours.
Child dosage (ages 0–17 years)
This medication has not been studied in children. It should not be used in people younger than 18 years.
Senior dosage (ages 65 years and older)
The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Take as directed
Tizanidine oral tablet is used for long-term or short-term treatment. It comes with serious risks if you don’t take it as prescribed.
If you stop taking the drug suddenly or don’t take it at all: If you stop taking tizanidine suddenly, you are at risk of withdrawal symptoms. This risk is higher if you’ve been taking high doses of the drug, or taking it for a long period of time. Withdrawal symptoms can include high blood pressure, a fast heart rate, or worsened muscle spasms. If you decide to stop this drug, your doctor should slowly decrease your dosage by 2–4 mg per day. If you don’t take this drug at all, your muscle spasms may not improve.
If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. If you miss too many doses, you may have withdrawal symptoms.
If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:
- extreme tiredness
- decreased heart rate
- severe decrease in blood pressure
- slowed breathing
If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.
What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.
How to tell if the drug is working: You should have fewer symptoms of muscle spasms. These symptoms can include muscle tightness, pain, or stiffness.
Keep these considerations in mind if your doctor prescribes tizanidine oral tablet for you.
- You can take tizanidine with or without food. But you should be consistent. Take it the same way each time.
- You can cut or crush the tablet.
- Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead.
- Store tizanidine tablets and capsules at 77°F (25°C). You can store them for a short time at temperatures between 59°F and 86°F (15°C and 30°C).
- Don’t store this medication in moist or damp areas, such as bathrooms.
A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.
When traveling with your medication:
- Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
- Don’t worry about airport x-ray machines. They can’t hurt your medication.
- You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
- Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.
Do not switch between capsule and tablet forms of tizanidine. Once you start taking one form, you should not change it.
You and your doctor should monitor certain health issues. This can help make sure you stay safe while you take tizanidine. These issues include:
- Kidney function. Blood tests can check how well your kidneys are working. If your kidneys aren’t working well, your doctor may lower your dosage of this drug.
- Liver function. Blood tests can check how well your liver is working. If your liver isn’t working well, your doctor may lower your dosage of this drug.
- Blood pressure. Your doctor may check your blood pressure to make sure that it does not get too low while you’re taking this drug.
You may need to have blood tests during your treatment with tizanidine. The costs of these tests will depend on your insurance coverage.
Many insurance companies require a prior authorization for this drug. This means your doctor may need to get approval from your insurance company before your insurance company will pay for the prescription.
There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.