Reviewed by: HU Medical Review Board | Last review date: July 2021. | Last updated: October 2022

Baclofen is a skeletal muscle relaxant used to treat muscle symptoms caused by multiple sclerosis (MS), including spasm, pain, and stiffness. It is classified as an antispastic agent. It inhibits both monosynaptic (single) and polysynaptic (multiple interwoven) reflexes at the spinal level. Baclofen is indicated for the relief of flexor spasms, clonus (spasms with rhythmic contractions), and muscular rigidity.

How does baclofen work?

Baclofen inhibits nerve reflex signaling in the spine and other nerve sites to reduce or eliminate spasm. The exact mechanism by which baclofen works to control spasticity is not known.

What are the brand names for baclofen?

Baclofen is sold under several different brand names in the US, including but not limited to:

  • Lioresal
  • Lioresal Intrathecal
  • Gablofen

Baclofen is most often taken as a tablet by mouth. It is also available as an injection, branded as Gablofen and Lioresal Intrathecal, formulated for intrathecal infusion, a method to deliver medication into the spinal fluid by an implantable pump.

What are the potential side effects of baclofen?

Taking baclofen can cause side effects for some people. The most common ones are:

  • Drowsiness
  • Dizziness
  • Weakness
  • Fatigue
  • Confusion
  • Headache
  • Insomnia (difficulty sleeping)
  • Low blood pressure
  • Nausea
  • Constipation
  • Urinary frequency
  • Impaired reaction time, some people should be advised to refrain from driving or operating heavy machinery.

These are not all the possible side effects of Baclofen. You should talk to your doctor about what to expect when taking Baclofen, and if you experience any side effects that are severe or won’t go away, it’s important to contact your healthcare provider immediately. When discontinuing baclofen, work with your healthcare provider to gradually reduce the dose. If you stop taking baclofen abruptly, there is a risk of hallucination and seizures.

Baclofen should be used with caution in people with MS who:

  • Have impaired kidney function
  • Have had a stroke
  • Are children under the age of 12
  • Are pregnant, unless the benefit clearly outweighs potential risk to the fetus
  • Use alcohol and other CNS depressants as the effects may be compounded

Patients should talk to their healthcare professional about other medications they are taking, possible side effects and any other medical condition they have before starting baclofen.

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