Sirdalud (Tizanidine) in Spain: What It Treats
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 29 October 2026
Sirdalud is the Spanish brand of tizanidine, a prescription-only muscle relaxant. What it treats, which medicines must not be mixed, and key warnings.
You don't have to figure this out alone
Dr. Pedro Yelamo Vera is an independent, bilingual GP licensed in Spain. Book a 15-minute video consultation in English or Spanish for €50, with a private electronic prescription issued under Spanish law when clinically appropriate.
Sirdalud is the Spanish brand of tizanidine, a prescription-only muscle relaxant. It eases painful muscle spasm linked to the neck or lower back, and stiffness (spasticity) after a stroke, in multiple sclerosis or after a spinal cord injury. In the US tizanidine is sold as Zanaflex. It often causes drowsiness and can lower blood pressure.
- Sirdalud (tizanidine) relaxes tight muscles. It acts on the nervous system, in the brain and spinal cord.
- It needs a prescription in Spain. It is licensed for adults.
- It must never be taken with fluvoxamine or ciprofloxacin, and not with severe liver disease.
- It can make you sleepy and dizzy. Do not stop it suddenly after long use: blood pressure and heart rate can rebound.
Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).
For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.
What is Sirdalud used for?
Tizanidine is an alpha-2 agonist. It calms the nerve signals that keep a muscle tight. The Spanish product information lists two uses in adults:
- Painful muscle spasm linked to the spine, in the neck or lower back, after surgery, or with a slipped disc.
- Spasticity: muscle stiffness caused by nerve conditions such as multiple sclerosis, stroke, spinal cord disease or injury, and cerebral palsy.
It is not a painkiller in the usual sense. It helps when tight muscle is part of the problem. A doctor usually pairs it with other steps, such as movement, heat or physiotherapy.
Sirdalud, Zanaflex and other muscle relaxants: which is which?
| Name | What it contains | Where |
|---|---|---|
| Sirdalud | Tizanidine tablets | Spain (prescription) |
| Zanaflex | Tizanidine | US (prescription) |
| Tizanidine (generic name) | Tizanidine | UK (prescription) |
| Yurelax | Cyclobenzaprine: a different muscle relaxant | Spain (prescription) |
| Robaxin | Methocarbamol: a different muscle relaxant | Spain (prescription) |
If a US doctor gave you Zanaflex, the Spanish name is Sirdalud. Yurelax and Robaxin are not the same medicine. They work in other ways and have other warnings. See our guides to Yurelax (cyclobenzaprine) and Robaxin (methocarbamol).
Do you need a prescription for Sirdalud in Spain?
Yes. Every Sirdalud pack is a medicamento sujeto a prescripción médica. A pharmacy cannot hand it over without a Spanish prescription, including a private electronic one. You can check the status on the AEMPS CIMA database.
A doctor needs to know your other medicines, your liver and kidney health and your blood pressure before starting it. That is why it is not sold over the counter.
A back or neck spasm that will not let go, or a muscle relaxant you used at home?
You can book a video visit with a GP licensed in Spain, in English or Spanish. He checks the cause, your other medicines and the warning signs, and explains the options.
What Sirdalud does not treat
- Pain without muscle spasm, such as a headache, toothache or joint pain from arthritis.
- Back pain with red flags: numbness in the groin, new trouble passing urine, leg weakness, fever, or pain after a bad fall. These need urgent care.
- Sciatica nerve pain on its own. Shooting leg pain comes from a nerve, not a tight muscle, and may need other treatment.
- Sleep problems. It can cause drowsiness, but it is not a sleeping tablet.
Our back pain page explains what a doctor looks for.
Which medicines must not be mixed with Sirdalud?
This is the most important safety point. Some medicines stop the body from breaking down tizanidine. Its level in the blood can then rise sharply, with very low blood pressure and heavy sleepiness.
- Fluvoxamine (an antidepressant) and ciprofloxacin (an antibiotic) must never be taken with it.
- Some other medicines are not advised with it, such as amiodarone, cimetidine and some other antibiotics of the same family as ciprofloxacin.
- The contraceptive pill also raises its level. Tell your doctor if you take it.
- Blood pressure tablets, including clonidine, can add to the drop in blood pressure.
- Alcohol, sleeping tablets, benzodiazepines, strong antihistamines and other sedatives add to the drowsiness.
Always show the doctor and pharmacist a full list of what you take, including anything bought without a prescription.
Other warnings before you take it
- Liver: it must not be used with severe liver disease. A doctor may check your liver with blood tests during treatment.
- Kidneys: with kidney disease the level can build up, so the doctor adjusts the plan.
- Driving: it can cause sleepiness, dizziness and low blood pressure. The Spanish leaflet advises against driving or using machines while you take it.
- Stopping: after long use, do not stop suddenly. Blood pressure and heart rate can jump. The doctor will lower it step by step.
- Pregnancy and breastfeeding: it is not advised in pregnancy unless the benefit clearly outweighs the risk, and not while breastfeeding.
Side effects and when to see a doctor
Very common side effects are sleepiness, dizziness, dry mouth, an upset stomach, tiredness and muscle weakness. Feeling light-headed when you stand up is also common: get up slowly. See a doctor if you notice:
- Fainting, or a slow or irregular heartbeat.
- Yellow skin or eyes, dark urine, or pain under the right ribs. These can be signs of liver trouble.
- Seeing things that are not there, or feeling confused.
- No real change in the spasm after a short trial.
- A racing heart or high blood pressure after a dose was missed or stopped.
Call 112 if there is swelling of the face, lips or throat, difficulty breathing, a faint you do not recover from quickly, or someone is very hard to wake.
Talking it through with a doctor by video
Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:
- Ask where the spasm or stiffness is, how it started and what you have already tried.
- Check for red flags in the back or neck that need urgent or in-person care.
- Go through your medicines, liver health and blood pressure before any muscle relaxant.
- Explain whether Sirdalud, another option, physiotherapy or a referral is the right next step.
He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.
A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.
This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.
Frequently asked questions
Is Sirdalud the same as Zanaflex?
Yes. Both contain tizanidine. Sirdalud is the Spanish brand and Zanaflex is the US brand. In the UK it is usually prescribed by its generic name.
Can I buy Sirdalud without a prescription in Spain?
No. Sirdalud is prescription-only in Spain. A doctor needs to check your other medicines, liver and blood pressure first.
Can I take Sirdalud at night?
It often causes drowsiness, so some people are told to take it in the evening. The timing is for your doctor to decide, based on your symptoms and other medicines.
Can I drink alcohol with Sirdalud?
No. Alcohol adds to the sleepiness and the drop in blood pressure that tizanidine can cause.
Is Sirdalud the same as Yurelax or Robaxin?
No. Yurelax is cyclobenzaprine and Robaxin is methocarbamol. They are different muscle relaxants with their own warnings and interactions.
Can I stop Sirdalud suddenly?
Not after long use. Stopping suddenly can raise blood pressure and heart rate. Your doctor will reduce it gradually.
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This content is written and reviewed by a licensed physician with reference to the following official health authorities.
