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 by temporarily relaxing muscle tone.

Zanaflex may also be used for purposes other than those listed in this medication guide.

What is the most important information I should know about Zanaflex?

Zanaflex is a short-acting medication that should be taken only for daily activities that require relief from muscle spasticity.

Do not take Zanaflex if you are also taking the antidepressant fluvoxamine (Luvox), or the antibiotic ciprofloxacin (Cipro). Do not use Zanaflex at a time when muscle tone is needed to assure safe balance and movement for 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 Zanaflex in a 24-hour period. Too much of this medication 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 Zanaflex. 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 Zanaflex.

What should I discuss with my healthcare provider before taking Zanaflex?

Do not use Zanaflex if you are allergic to tizanidine, or if you are also taking the antidepressant fluvoxamine (Luvox), or the antibiotic ciprofloxacin (Cipro).

Before using Zanaflex, tell your doctor if you are allergic to any drugs, or if you have:

liver disease;
kidney disease;
high or low blood pressure; or
a history of «Long QT syndrome.»

If you have any of these conditions, you may not be able to use Zanaflex, or you may need a dosage adjustment or special tests during treatment.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. It is not known whether Zanaflex passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby. In older adults, Zanaflex may take much longer to clear from the body. Follow your doctor’s instructions about your specific dosage and medication schedule.

How should I take Zanaflex?

Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.

Your doctor may occasionally change your dose to make sure you get the best results from this medication.

Take this medication with a full glass of water.

Zanaflex is a short-acting medication, and its effects will be most noticeable between 1 and 6 hours after you take it. This medication should be taken only for daily activities that require relief from muscle spasticity.

In most cases, you may take up to three doses in one day if needed. Allow 6 to 8 hours to pass between doses.
Carefully follow your doctor’s instructions about taking this medication with or without food. Taking Zanaflex tablets with food can increase the levels of Zanaflex in your blood stream, but taking Zanaflex capsules with food can decrease the levels.

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) in a 24-hour period. Too much of this medication can damage your liver.

To be sure this medication is not causing harmful effects, your liver function will need to be tested on a regular basis. Do not miss any scheduled visits to your doctor.

You may have withdrawal symptoms such as dizziness, fast heart rate, tremors, anxiety, and increased spasticity when you stop using Zanaflex after using it over a long period of time. Do not stop using this medication suddenly without first talking to your doctor. You may need to use less and less before you stop the medication completely.

Store Zanaflex at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at your next regularly scheduled time. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include drowsiness, confusion, slow heart rate, shallow breathing, feeling light-headed, fainting, or coma.

What should I avoid?

Zanaflex can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Dizziness is most likely to occur when you rise from a sitting or lying position. Get up slowly to prevent dizziness and a possible fall. Do not use Zanaflex at a time when muscle tone is needed to assure safe balance and movement for certain activities. In some situations, it may endanger your physical safety to be in a state of reduced muscle tone. 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 Zanaflex. 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 Zanaflex.

Zanaflex side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:

feeling light-headed, fainting, slow heart rate;
hallucinations, confusion, unusual thoughts or behavior;
nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
burning or pain when you urinate.

Less serious Zanaflex side effects may be more likely to occur, such as:

drowsiness or dizziness;
feeling anxious or nervous;
numbness or tingling;
stomach pain, diarrhea, constipation, vomiting;
fever;
dry mouth;
muscle weakness, back pain;
increased muscle tone or spasms; or
sweating or skin rash.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

What other drugs will affect Zanaflex?

Before taking Zanaflex, tell your doctor if you are using any of the following drugs:

acyclovir (Zovirax);
cimetidine (Tagamet);
famotidine (Pepcid);
ticlopidine (Ticlid),
zileuton (Zyflo);
birth control pills;
antibiotics such as enoxacin (Penetrex), gatifloxacin (Tequin), levofloxacin (Levaquin), lomefloxacin (Maxaquin), moxifloxacin (Avelox), ofloxacin Floxin), sparfloxacin (Zagam), trovafloxacin (Trovan), or norfloxacin (Noroxin);
blood pressure medications such as clonidine (Catapres), guanabenz (Wytensin), guanfacine (Tenex), or methyldopa (Aldomet); or
heart rhythm medications such as amiodarone (Cordarone, Pacerone), mexiletine (Mexitil), propafenone (Rhythmol), and verapamil (Calan, Covera, Isoptin).

If you are using any of these drugs, you may not be able to use Zanaflex, or you may need dosage adjustments or special tests during treatment.

There may be other drugs not listed that can affect Zanaflex. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.