Zanaflex

Medically Reviewed by Harshi Dhingra, M.D.

Last Reviewed: Jun 22, 2022

Warnings

What are the risks of taking Zanaflex (tizanidine)?

Zanaflex can cause serious health problems, especially in certain high-risk group
Some of the serious risks of this medication include:

Low blood pressure: Zanaflex works in the same way as some blood pressure-lowering medicines. It can therefore cause a drop in blood pressure. This risk is higher in people over the age of 65 and those who are on medications for high blood pressure. Standing up too fast from a sitting or lying position can cause dizziness or lightheadedness during Zanaflex treatment. To avoid this, stand up slowly.
Drug interactions: Zanaflex should not be used with fluvoxamine or ciprofloxacin because the combination can cause dangerously low blood pressure. Zanaflex can also interact with multiple other medications, including over-the-counter medications. Be sure to tell your pharmacist and doctor about all the medications you take, including dietary supplements, vitamins, and herbal products, even if you take them only occasionally.
Liver damage: In some people, Zanaflex can damage the liver. Therefore, this medicine may not be right for people with pre-existing liver disease. Your doctor may advise regular blood tests to check your liver function if you will be on Zanaflex for a long time.
Kidney problems: The kidneys process Zanaflex. The medication can build up in the body if the kidneys are not working properly. This can make Zanaflex side effects more intense. Your doctor might give you another muscle relaxant or give you a lower dose of Zanaflex if you have a history of kidney problems.
Drowsiness: Zanaflex can make you drowsy and affect your focus and concentration. This risk is higher in people over age 65 and those who take other medicines that cause drowsiness. Do not drive, operate heavy machinery, or do anything that requires concentration until you know how Zanaflex affects you.
Allergic reaction: Rarely, Zanaflex can lead to a severe allergic reaction with anaphylaxis (throat closing). If you experience symptoms such as hives, rash, swelling of the lips, tongue, or mouth, or difficulty breathing or swallowing while on this medicine, seek medical attention right away.
Hallucinations: In a small number of people, Zanaflex can cause hallucinations (seeing or hearing things that are not there). Your healthcare provider can give you some other muscle relaxant if this happens.
Withdrawal: Stopping Zanaflex abruptly can lead to withdrawal symptoms such as high blood pressure, fast heartbeat, and muscle stiffness. This is more likely to occur if you have been taking Zanaflex at doses greater than 20 mg per day for more than 9 weeks and stop it suddenly. It is also more likely if you take narcotic medicines like morphine or oxycodone with Zanaflex. Talk to your healthcare professional about coming off Zanaflex gradually and safely.

Your doctor or pharmacist may prescribe other treatments for muscle spasticity and rigidity if you are at a high risk of complications from Zanaflex.

What should I tell my doctor before starting Zanaflex (tizanidine)?

Tell your health care professional about all your medical conditions. Zanaflex may not be suitable for people with certain medical conditions like liver or kidney disease.

Also, tell your doctor about all your medications, including prescription drugs, over-the-counter medications, dietary supplements, vitamins, and herbal products. This can help avoid serious drug interactions. Specifically, tell your doctor if you are taking ciprofloxacin (Cipro) or fluvoxamine. You cannot take Zanaflex if you are on these medications.

Tell your doctor if you have an allergy to tizanidine or any other medications. Your local pharmacy can provide you with a list of ingredients in Zanaflex tablets and capsules.

Tell your doctor if you are pregnant, breastfeeding, or plan to become pregnant.

What precautions should I take while on Zanaflex (tizanidine)?

Keep all appointments with your healthcare providers. They may order some tests to keep an eye on liver or kidney function from time to time.

Zanaflex can make you dizzy, lightheaded, and drowsy. Do not drive, operate heavy machinery, or do anything that requires concentration and attention before knowing how this medication affects you. Also, keep in mind that alcohol can add to the drowsiness caused by this medicine.

Zanaflex can cause low blood pressure. This can make you dizzy or lightheaded when you arise from a lying or sitting position. To avoid this, get up slowly (rest your feet on the floor for a few minutes before standing).

Tizanidine (Zanaflex) can cause low muscle tone. Be careful when doing any activities that require balance and coordination.

Tell your doctor if you become pregnant while taking Zanaflex. This medicine should be used with caution in women who are pregnant or breastfeeding.

Tell your doctor or dentist that you are on Zanaflex if you are having surgery, including dental surgery.

What drugs can interact with Zanaflex (tizanidine)?

Taking Zanaflex with some other medications can affect how it works. Drug interactions can also increase the risk of serious side effects. Your healthcare provider may choose a different muscle relaxer for you, change the dose or frequency of one or both medicines, or monitor you carefully for side effects if there are known interactions between Zanaflex and some of your other medicines.

Taking Zanaflex is not recommended if you are taking fluvoxamine or ciprofloxacin (Cipro). There can be interactions between Zanaflex and medicines such as:

acyclovir (Zovirax)
certain medications for irregular heartbeat (Pacerone, Cordarone)
cimetidine (Tagamet)
famotidine (Pepcid)
clonidine (Catapres)
diazepam (Valium) and other sleeping pills, sedatives, and tranquilizers
dantrolene (Dantrium)
baclofen
oral contraceptive pills
fluoroquinolones like gemifloxacin, levofloxacin, moxifloxacin, norfloxacin, and ofloxacin
certain medications used to treat anxiety or seizures
certain medications used to treat high blood pressure

This list does not describe all possible Zanaflex interactions. Give your health care provider a complete list of your medications, including prescription and non-prescription drugs, vitamins and supplements, and herbal remedies. Also, tell your health care provider if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription drugs.

Find the best discount on Zanaflex »