Tizanidine (Zanaflex): Uses, Warnings, and Key Facts
Quick summary Tizanidine is a muscle relaxant used for muscle spasms and spasticity. In the United States, the brand name is Zanaflex. It may cause drowsiness, dizziness, and low blood pressure, so safety checks...
This content is for educational purposes only and does not replace medical advice, diagnosis or treatment from a qualified healthcare professional.
Quick summary
Tizanidine is a muscle relaxant used for muscle spasms and spasticity. In the United States, the brand name is Zanaflex. It may cause drowsiness, dizziness, and low blood pressure, so safety checks and the official medication guide matter.
Medical disclaimer: This article is for general information only and does not replace advice from a doctor, pharmacist, or the official FDA medication guide. Do not use it to diagnose a condition or to change any prescribed treatment.
What is tizanidine?
Tizanidine is a medicine used to treat muscle spasms. The active ingredient is tizanidine hydrochloride (HCl). In the United States, the brand name is Zanaflex.
How tizanidine works
Tizanidine is an alpha-2 adrenergic receptor agonist. It appears to reduce spasticity by increasing presynaptic inhibition of motor neurons.
What is tizanidine used for?
The original content describes two main uses:
- Painful muscle spasms linked to static or functional spine disorders, such as cervical and lumbar syndromes, or after surgery.
- Spasticity due to neurological disorders, including multiple sclerosis, chronic myelopathy, degenerative spinal cord disorders, stroke, and cerebral palsy.
Exact use depends on the condition being treated and the prescribing information for the specific product.
How it is taken
Tizanidine is used orally. The tablets are taken with a glass of water.
Dosage information from the original content
The following dosing details were included in the source content. They are shown here for reference only and should be verified in the official leaflet or with a healthcare professional.
| Use | Source dosing details |
|---|---|
| Painful muscle spasms | 2–4 mg every 8 hours; in severe cases, an additional 2 or 4 mg at night. |
| Spasticity due to neurological disorders | Initial 2 mg every 8 hours, increasing every 3–7 days by 2–4 mg until 12–24 mg/day in 3 or 4 doses; maximum 36 mg/day. |
| Renal insufficiency (Clcr < 25 ml/min) | Initial 2 mg/day, then adjust according to response and tolerance. |
Contraindications listed in the source
The original content lists the following contraindications:
- Hypersensitivity
- Concomitant use with fluvoxamine or ciprofloxacin
Warnings and precautions
- Liver problems: The source notes caution in liver failure or impaired liver function.
- Older adults: Extra caution is advised in elderly patients.
- Low blood pressure: Hypotension may occur and can be serious.
- Do not stop suddenly: Abrupt interruption may lead to rebound hypertension and tachycardia.
- Monitoring: Periodic liver monitoring is mentioned in the source.
- Sleepiness and hallucinations: Sedation and hallucinations are listed as possible effects.
- Children: The source says it is not recommended for children.
- Drug interactions: Avoid concomitant use with other CYP1A2 inhibitors, according to the source.
Liver impairment
The source advises starting with lower doses and increasing according to tolerability.
Renal impairment
The source advises caution and starting at 2 mg/day, with dose adjustment based on response and tolerance.
Drug interactions mentioned in the source
The original content lists medicines that may increase the action of tizanidine, including:
- Amiodarone
- Mexiletine
- Propafenone
- Cimetidine
- Enoxacin
- Pefloxacin
- Ciprofloxacin
- Norfloxacin
- Rofecoxib
- Oral contraceptives
- Ticlopidine
If you take any prescription medicine, over-the-counter product, or herbal supplement, the official leaflet and a pharmacist can help check for interactions.
Pregnancy and breastfeeding
Pregnancy: The source states that no clinical data are available in humans and that tizanidine should not be used unless the benefit clearly outweighs the risks.
Breastfeeding: The source says it is not known whether tizanidine passes into human milk, and it is not recommended during breastfeeding.
Effects on driving and machinery
Tizanidine may cause drowsiness, dizziness, or symptoms of low blood pressure. Because of this, the source says driving vehicles or operating machinery is not recommended while taking this medicine.
Possible adverse reactions
The original content lists the following side effects:
- Drowsiness
- Dizziness
- Bradycardia
- Hypotension
- Dry mouth
- Fatigue
- Decreased blood pressure
What to verify with a doctor or pharmacist
Because product details can vary, it is important to confirm the following in the official medication guide or with a healthcare professional:
- The exact reason tizanidine was prescribed
- The correct dose and timing for the specific product
- Whether any liver or kidney issues affect use
- Whether other medicines may interact with it
- Whether it is appropriate during pregnancy or breastfeeding
FAQ
▸ What is tizanidine used for?
The source says tizanidine is used for painful muscle spasms and for spasticity related to certain neurological disorders.
▸ Is Zanaflex the same as tizanidine?
Yes. The source identifies Zanaflex as the U.S. brand name for tizanidine.
▸ Can tizanidine cause drowsiness?
Yes. Drowsiness is listed among the adverse reactions in the original content.
▸ Does tizanidine interact with other medicines?
Yes. The source lists several interacting medicines, including ciprofloxacin, fluvoxamine, and other drugs that may increase its effect.
▸ Is tizanidine recommended in pregnancy or breastfeeding?
The source says human pregnancy data are not available and that it is not recommended during breastfeeding.
Safety reminder: Tizanidine can cause sleepiness, dizziness, and low blood pressure. If you have liver or kidney problems, take other medicines, or are pregnant or breastfeeding, confirm the official guidance with a healthcare professional and the FDA medication guide.
Sources and reference links
The original content was compiled using ingredient and regulatory reference resources. Helpful reference links include:
- FDA Medication Guide search
- UNII: 6AI06C00GW
- ChemIDplus
- DrugPortal
- PubChem CID: 5487
- NCI Thesaurus: C61976
Medical disclaimer
This content is for educational purposes only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. Always ask a doctor, pharmacist or qualified healthcare professional before starting, stopping or changing any medicine.
Sources and verification
The following sources or official references are listed to support verification of the medicine information discussed in this article.
Medicine information can change and may vary depending on country, product formulation, patient history and professional guidance. Always check official medicine information and ask a healthcare professional for personal medical questions.