Zanaflex (Tizanidine)

How does it work?

Zanaflex tablets contain the active ingredient tizanidine, which is a type of medicine known as an alpha-2-adrenoceptor agonist. Tizanidine is used as a muscle relaxant, in conditions such as multiple sclerosis and spinal cord injury or disease.

Tizanidine works by blocking the alpha-2-adrenoceptors in the central nervous system (brain and spinal cord). The effect of this is to 'damp down' the nerve signals that are carried in the spinal cord to the muscles. This reduces the contraction and tension in the muscles.

In conditions where there is painful or disabling muscle spasm, tizanidine can help to reduce stiffness and enable people to undergo rehabilitation that increases their mobility.

What is it used for?

  • Treatment of muscle spasticity associated with multiple sclerosis or with spinal cord injury or disease.


  • This medicine may cause drowsiness. If affected do not drive or operate machinery.
  • Your liver function should be monitored while you are taking this medicine. Symptoms that may suggest a liver problem include persistent nausea and vomiting, abdominal pain, or the development of jaundice (a yellow colouring to the skin and the whites of the eyes). Consult your doctor if you experience any of these symptoms.

Use with caution in

  • Decreased kidney function.
  • Elderly people.

Not to be used in

  • Severe decreased liver function.
  • People taking the anitdepressant fluvoxamine or the antibiotic ciprofloxacin.
  • Pregnancy.
  • Breastfeeding.
  • This medicine is not recommended for children and adolescents under 18 years of age, as there is no information regarding its safety and efficacy in this age group.
  • Rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption (Zanaflex tablets contain lactose).

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine should be used with caution during pregnancy and breastfeeding. Seek medical advice from your doctor.

Label warnings

  • This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drinks.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Dry mouth.
  • Drowsiness.
  • Nausea.
  • Fatigue.
  • Dizziness.
  • Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain.
  • Low blood pressure (hypotension).
  • Difficulty in sleeping (insomnia).
  • False perceptions of things that are not really there (hallucinations).
  • Slow heart rate (bradycardia).
  • Skin reactions, such as itching, rash.
  • Alteration in results of liver function tests.
  • Inflammation of the liver (hepatitis) or liver failure (see warning above).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

The following medicines may increase the level of tizanidine in the blood and so could increase the risk of side effects, the manufacturer recommends that these are not taken in combination with this medicine:

  • antiarrhythmics, such as amiodarone, mexiletine, propafenone
  • cimetidine
  • fluvoxamine
  • quinolone antibiotic, such as ciprofloxacin, enoxacin or norfloxacin.

There may be an increased risk of abnormal heart beats if this medicine is taken in combination with any of the following medicines, and the manufacturer recommends that this medicine is used with caution in people taking any of these:

  • beta blockers, such as atenolol, propanolol
  • certain medicines used to treat abnormal heart rhythms (antiarrhythmics) such as quinidine, disopyramide, procainamide, amiodarone, sotalol
  • digoxin.

There may be an increased risk of a drop in blood pressure that makes you feel dizzy if this medicine is taken in combination with other medicines that can lower blood pressure, for example medicines to treat high blood pressure (antihypertensives). Tell your doctor if you feel dizzy after starting treatment with this medicine, as your doctor may need to adjust the dose of your blood pressure medicine.

There may be an increased risk of drowsiness and sedation if this medicine is taken with any of the following (which can also cause drowsiness):

  • alcohol
  • barbiturates, eg phenobarbital, amobarbital
  • benzodiazepines, eg diazepam, temazepam
  • tricyclic antidepressants, eg amitriptyline
  • narcotics, eg morphine, codeine
  • sedating antihistamines, eg eg chlorphenamine
  • sleeping tablets, eg zopiclone.

Oral contraceptives may reduce the clearance of tizanidine from the body, thus increasing the amount in the blood. This increases the risk of side effects associated with tizanidine.

Other medicines containing the same active ingredient

Tizanidine tablets are available without a brand name, ie as the generic medicine.