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.
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:
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;
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.
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.
-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:
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.
The maximum effect of tizanidine occurs about 1 hour to 2 hours after taking a dose. It wears off in about 3 to 6 hours after taking it. Tizanidine is typically given no more than 3 times a day.
Tizanidine is not listed as a controlled substance by the U.S. Drug Enforcement Administration (DEA). Abuse potential has not been evaluated in human studies.
Tizanidine is known to cause low blood pressure. In some cases, it may cause low blood pressure that is so low that you could faint or pass out. The chances of fainting can be lowered if your doctor raises the dose of tizanidine very slowly. You may also have to be careful when you move from a sitting position to a standing position. In clinical trials, the most common side effects of tizanidine were dry mouth, sleepiness, dizziness and asthenia (defined as weakness, fatigue and/or tiredness).
Tizanidine can cause sleepiness, but it has not been approved by the U.S. Food and Drug Administration (FDA) to treat sleep disorders. Tizanidine is a skeletal muscle relaxant. It is approved by the FDA to help relieve muscle spasms.
Tizanidine normally starts working 1 to 2 hours after taking it. It wears off about 3 hours to 6 hours after taking it. Tizanidine can be taken up to 3 times a day to help relieve muscle spasms.
Tizanidine may be addictive, but it has not been evaluated in human studies. Withdrawal symptoms have been reported after abruptly stopping tizanidine, but abuse of other medications concomitantly was suspected in these cases. Dosing should be tapered off to avoid possible withdrawal symptoms.
Tizanidine is not known to cause weight gain. In clinical trials, the most common side effects of tizanidine were dry mouth, sleepiness, dizziness and asthenia (defined as weakness, fatigue and/or tiredness).
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