Zanaflex (tizanidine hydrochloride)

Reviewed by: HU Medical Review Board | Last reviewed: April 2023

Zanaflex® is a medicine 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.1

What are the ingredients in Zanaflex?

The active ingredient in Zanaflex is tizanidine hydrochloride (HCl).1

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.1

What are the possible side effects?

Many clinical trials evaluated the safety and efficacy of Zanaflex. The most common side effects experienced by those taking Zanaflex include:1

  • Dry mouth
  • Sleepiness or drowsiness
  • Weakness, fatigue, or tiredness
  • Dizziness
  • Low blood pressure
  • Slow heart rate

These are not all the possible side effects of Zanaflex. Talk to your doctor about what to expect when taking Zanaflex. You also should call your doctor if you have any changes that concern you when taking Zanaflex.

Other things to know 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. Your doctor will give you instructions on which method of administration is best for you.1

Before starting Zanaflex, talk with your doctor if you:1

  • 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 ciprofloxacin
  • Are pregnant or planning to get pregnant, as there is limited information on the use of Zanaflex in pregnancy. Based on data from animal studies, Zanaflex may harm unborn babies.

People with the above conditions should be monitored closely while taking Zanaflex.1

Do not stop taking Zanaflex all of a sudden. Instead, your doctor will lower your dose slowly to prevent side effects.1

Before beginning treatment for MS, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

For more information, read the full prescribing information of Zanaflex.

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