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Zanaflex (tizanidine hydrochloride)

Zanaflex® is a medication indicated for the management of spasticity. It has a short acting therapeutic effect so treatment should be reserved for those daily activities and times when relief from these symptoms of multiple sclerosis (MS) is most important. It comes in capsule and tablet forms and is taken by mouth. Capsules come in varied strengths of 2 mg, 4 mg and 6 mg; tablets come in 2mg and 4 mg.

What are the ingredients in Zanaflex?

The active ingredient in Zanaflex is tizanidine hydrochloride (HCl)

How does Zanaflex work?

It is thought that Zanaflex works by blocking nerve impulses that cause muscles to tighten, thereby reducing the frequency and severity of spasticity.

What are the possible side effects of Zanaflex?

Many clinical trials evaluated the safety and efficacy of Zanaflex. The most common side effects experienced by those taking Zanaflex include:

  • Dry mouth
  • Somnolence/ sedation (sleepiness or drowsiness)
  • Asthenia (weakness, fatigue or tiredness)
  • Dizziness
  • UTI (urinary tract infection) or urinary frequency
  • Nausea
  • Hypotension (low blood pressure)
  • Hallucinations/psychotic like symptoms

This is not an exhaustive list of all potential side effects of Zanaflex. For more information, consult your doctor or healthcare provider. If you notice any new or worsening side effects when taking Zanaflex, contact your doctor or healthcare provider.

Things to note about Zanaflex

Zanaflex is a central alpha-2-adrenergic agonist that decreases activity in the sympathetic nervous system. It is used for the management of spasticity in people with MS. Zanaflex comes in capsule and tablet form; they work in a similar way in a fasting state but differently when taken with food. Food increases the rate of absorption. The prescribing physician should provide clear instructions on which method of administration is best for each patient. Following the instructions will make sure the drugs are absorbed, distributed and metabolized in the most effective, safest way possible.

Zanaflex is a white crystalline powder when contained in capsules. The tablets are white and are uncoated.

Before starting Zanaflex, talk with your doctor if you:

  • Have a history of hypersensitivity to tizanidine hydrocholoride
  • Have hepatic (liver) impairment
  • Have renal (kidney) impairment
  • Take certain medications (CYP1A2 inhibitors) such as fluvoxamine or ciproflaxin
  • Are pregnant or planning to get pregnant, as there is limited information on the use of Zanaflex in pregnancy.

Individuals with the above conditions should be monitored closely while taking Zanaflex.

Dosing information

Zanaflex capsules are available in 3 strengths: 2mg, 4mg, 6mg. Tablets come in 2mg and 4mg. The medication is most effective 1-2 hours after dosing and lasts for 3-6 hours.

The recommended starting dose is 2 mg and can be repeated every 6-8 hours up to a maximum of 3 doses in a 24-hour period. Dosage can be increased by 2- 4mg per dose, up to a maximum daily dose of no more than 36 mg.

If you plan to stop taking Zanaflex, slowly decrease the dosage to minimize the risk of withdrawal and rebound effects including high blood pressure and an increased heart rate. Patients should avoid consuming alcohol while taking Zanaflex.

For additional details, read the full prescribing information of Zanaflex.

Written by: Jonathan Simmons | Last reviewed: July 2019.
Zanaflex (tizanidine) Prescribing Information. Acorda Therapeutics, Inc; Hawthorne, NY: 2010.