A muscle relaxant for muscle spasm
Tizanidine
A muscle relaxant that eases muscle stiffness and spasm (spasticity), often used in multiple sclerosis.
What is Tizanidine?
Tizanidine (Zanaflex) is a muscle relaxant used to ease muscle stiffness and spasm (spasticity), such as in multiple sclerosis or after a spinal injury. It works on the nervous system to calm overactive muscle reflexes. It often causes drowsiness, can lower blood pressure, and needs liver checks.
Education and reference only. This is a plain-language guide to Tizanidine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Tizanidine is a muscle relaxant used to reduce muscle stiffness and painful spasms (spasticity), for example in multiple sclerosis or after a spinal cord injury. It works on the nervous system rather than directly on the muscle. In the UK it is a prescription-only medicine, usually started at a low level and built up gradually.
How it works
Tizanidine acts on alpha-2 receptors in the spinal cord and brain, dampening the nerve signals that drive overactive muscle reflexes. This reduces the tightness and spasms of spasticity, often making movement and comfort easier. Because it acts on the central nervous system, it commonly causes drowsiness and can lower blood pressure.
Company & origin
Originated / developed by: Originator brand Zanaflex.
A centrally acting muscle relaxant used in the UK for spasticity, for example in multiple sclerosis.
Practical use
How to take Tizanidine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it as prescribed; the dose is usually built up slowly to limit drowsiness and dizziness.
- It often causes drowsiness, so avoid driving or using machinery until you know how it affects you.
- Avoid alcohol, which adds to the drowsiness and the drop in blood pressure.
- Do not stop it suddenly after taking it regularly — your prescriber will reduce it gradually.
- If you miss a dose, take it when you remember unless the next is due soon — do not double up.
Weighing it up
Advantages & disadvantages of Tizanidine
Advantages
- Eases muscle stiffness and painful spasms, which can improve comfort and movement.
- A useful option for spasticity in conditions such as multiple sclerosis.
- The dose can be adjusted to balance benefit against drowsiness.
Disadvantages
- Commonly causes drowsiness, dry mouth and low blood pressure.
- Needs liver blood-test monitoring and must not be combined with certain medicines.
- Must be stopped gradually, as stopping suddenly can cause rebound high blood pressure.
Practical use
Good to know
Drowsiness, dry mouth and low blood pressure are common, especially as the dose is increased, so it is usually built up slowly. Your liver function should be checked before and during treatment, as tizanidine can occasionally affect the liver. It should not be combined with certain medicines that raise its levels, including the antibiotic ciprofloxacin and the antidepressant fluvoxamine, as this can cause dangerously low blood pressure and heavy sedation. Do not stop it suddenly after regular use, as this can cause a rebound rise in blood pressure and heart rate — it is reduced gradually.
Who should not take it / use with caution
- People with significant liver impairment, or who take ciprofloxacin or fluvoxamine, should not use it.
- Used with caution in people with low blood pressure, heart problems, or kidney impairment.
- Older people are more sensitive to its effects; check pregnancy and breastfeeding with a clinician.
Monitoring
- Liver function before and during treatment.
- Blood pressure and drowsiness, especially as the dose is increased.
- Whether muscle stiffness and spasms improve as intended.
Side effects
- Drowsiness, dizziness and dry mouth.
- Low blood pressure, weakness or feeling faint, especially when standing up.
- Rarely, liver problems (such as nausea, yellowing of the skin or dark urine) needing prompt review.
Key interactions
- Ciprofloxacin and fluvoxamine greatly raise tizanidine levels and must not be combined with it.
- Blood pressure medicines and alcohol add to its blood-pressure-lowering and sedating effects.
- Other sedating medicines increase drowsiness; tell your prescriber about all your medicines.
Available as: Tablets and capsules taken by mouth.
Answers
Tizanidine: frequently asked questions
What is tizanidine used for?
It is used to ease muscle stiffness and painful spasms (spasticity), for example in multiple sclerosis or after a spinal cord injury, by calming overactive muscle reflexes.
Why can't I take it with ciprofloxacin?
Ciprofloxacin and fluvoxamine greatly increase tizanidine levels in the body, which can cause dangerously low blood pressure and heavy drowsiness, so these combinations are avoided.
Will it make me drowsy?
Yes, drowsiness is common, especially as the dose is built up. Avoid driving until you know how it affects you, and do not drink alcohol with it.
Why do I need liver blood tests?
Tizanidine can occasionally affect the liver, so your liver function is checked before and during treatment to catch any problems early.
Can I stop taking it suddenly?
No — stopping suddenly after regular use can cause a rebound rise in blood pressure and heart rate, so your prescriber will reduce the dose gradually.
The wider class
About Muscle relaxants
Tizanidine belongs to the muscle relaxants class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF
- NICE CKS
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