Zanaflex vs. Flexeril for Fibromyalgia


Pain from fibromyalgia can be quite bothersome. Often, it can have a severe impact on your quality of life, making even normal tasks difficult. Two muscle relaxants called Zanaflex and Flexiril (cyclobenzaprine) are among the drugs used to treat fibromyalgia. Learn how they compare.

Drug features

Flexeril was one popular brand name for the drug cyclobenzaprine. Although the brand Flexeril is no longer available, many doctors still use its name to refer to cyclobenzaprine.  Cyclobenzaprine likely treats fibromyalgia by increasing the effects of norepinephrine, a substance in your brain and spinal cord that helps reduce pain signals.

Zanaflex is the brand name for the drug tizanidine. It’s believed to work by reducing the release of substance P in your brain and spinal cord. Substance P is a chemical that helps increase pain signals to and from the brain.

Both of these drugs work to treat fibromyalgia pain and decrease muscle spasms.

The table below summarizes other drug features of both tizanidine and cyclobenzaprine.

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*Cyclobenzaprine is no longer sold under the brand name Flexeril.
† If you’ve been taking this drug for longer than a few weeks, don’t stop taking it without talking to your doctor. You’ll need to taper off the drug slowly to avoid withdrawal symptoms such as anxiety, sweating, nausea, and trouble sleeping.
†† A high misuse potential means you can get addicted to this drug. Be sure to take it exactly as your doctor tells you to. If you have questions or concerns, talk with your doctor


Alcohol and withdrawal risks

Do not drink alcohol while using either tizanidine or cyclobenzaprine. Drinking alcohol with either drug may cause severe drowsiness and make you much less alert. This effect can make activities such as driving difficult and unsafe.

You also should not stop taking tizanidine or cyclobenzaprine suddenly. Doing so can cause withdrawal symptoms. This is especially likely if you’ve been taking either drug for a long time.

Withdrawal symptoms of tizanidine include:

  • high blood pressure
  • fast heart rate
  • increased muscle tone
  • tremors
  • anxiety

Withdrawal symptoms of cyclobenzaprine include:

  • nausea
  • headache
  • tiredness

If you need to stop taking either drug, your doctor will slowly lower your dosage over time.

Cost, availability, and insurance

Tizanidine and cyclobenzaprine are both available as brand-name and generic drugs. Generally, the brand-name drugs are more expensive than the generics. Between the generics, tizanidine is more expensive than cyclobenzaprine. Both drugs are available in most pharmacies.

Health insurance plans usually cover the generic forms of both drugs without prior authorization. In many cases, insurance companies will require a prior authorization for Zanaflex or Amrix.

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