Baclofen vs. Flexeril Side Effects, Strengths, Interactions

  • Medical Editor: John P. Cunha, DO, FACOEP
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

Baclofen vs. Flexeril quick comparison of differences

  • Baclofen (Gablofen, Lioresal) and Flexeril (cyclobenzaprine) are muscle relaxants. Baclofen us used in people with multiple sclerosis to manage symptoms and signs of muscle spacicity and pain. Flexeril is used used for the treatment of short-term relief of skeletal muscle spasms and pain associated with short-term painful muscle and skeletal problems. 
  • Baclofen is not approved or recommended for the treatment of skeletal muscle spasms due to rheumatoid diseases, stroke, cerebral palsy, or Parkinson's disease. Flexeril is not approved for the treatment of multiple sclerosis symptoms.
  • Side effects of baclofen and Flexeril that are similar include:
  • Side effects of baclofen that are different and do not occur with Flexeril include:
  • Side effects of Flexeril that are different and do not occur with baclofen include:
  • It is not recommended to take baclofen and Flexeril at the same time because when taken together they increase sedation and drowsiness.
  • Suddenly stopping oral baclofen may cause seizures and hallucinations. Suddenly stopping Flexeril after prolonged use can lead to symptoms of withdrawal such as headaches, nausea, and weakness.
  • Brand names for baclofen include Gablofen and Lioresal.
  • The brand name Flexeril has been discontinued in the U.S. Brand names of cyclobenzaprine available in the U.S. are Amrix and Fexmid.

What is baclofen? What is Flexeril? How do they work?

Baclofen is a medication that relaxes skeletal muscles. Chemically, baclofen is related to gamma-aminobutyric acid (GABA), a naturally occurring neurotransmitter in the brain. Neurotransmitters are chemicals that nerves use to communicate with one another. GABA released by some nerves causes the activity of other nerves to decrease. It is thought that baclofen acts like GABA and blocks the activity of nerves within the part of the brain that controls the contraction and relaxation of skeletal muscle.

Flexeril (cyclobenzaprine) is a muscle relaxant. Flexeril is used with rest and physical therapy for short-term relief of muscle spasms associated with acute painful muscle and skeletal conditions. It is only for short-term use, up to two or three weeks.

What are the uses for baclofen vs. Flexeril?

Baclofen uses

Baclofen is used for treating spasm of skeletal muscles, muscle clonus, rigidity, and pain caused by disorders such as multiple sclerosis. It is also injected into the spinal cord (intrathecal) for management of severe spasticity.

Flexeril uses

Cyclobenzaprine is used with rest and physical therapy for short-term relief of muscle spasms associated with acute painful muscle and skeletal conditions. It is only for short-term use, up to two or three weeks.

What are the differences between the side effects of baclofen vs. Flexeril? Can I take them together?

Baclofen side effects

Common side effects of baclofen are:

Abrupt discontinuation of oral baclofen may cause seizures and hallucinations. Abrupt discontinuation of intrathecal baclofen may result in:

  • High fever
  • Rebound spasticity
  • Muscle rigidity

Rhabdomyolysis (muscle breakdown) that can progress to failure of several organs, including the kidney, and even death.

Flexeril side effects

The most common side effects of cyclobenzaprine include:

Other reported side effects include:

Possible serious side effects include:

Abruptly stopping Flexeril after prolonged therapy may cause withdrawal symptoms such as headaches, nausea, and weakness.

You should not take Flexeril and baclofen together because it increases sleepiness and sedation.

Which muscle relaxant is stronger, baclofen or Flexeril?

Baclofen dosage

The usual starting dose of oral baclofen for treating spasticity in adults is 5 mg given three times daily. Based on the response, the dose can be increased by 5 mg every three days to a maximum of 80 mg/day in divided doses.

Flexeril dosage

The recommended dose of cyclobenzaprine dose is 5 or 10 mg three times daily using immediate release tablets or 15 or 30 mg once daily using extended release tablets.

What are the differences between the drug interactions of baclofen vs. Flexeril

Baclofen drug interactions

  • Use of baclofen with other drugs that also depress the function of nerves may lead to additional reduction in brain function.
  • In addition to the risk of depressing brain function, the use of baclofen and tricyclic antidepressants (for example, amitriptyline [Elavil, Endep], doxepin [Sinequan, Adapin]) together may cause muscle weakness.
  • Use of baclofen and monoamine oxidase inhibitors (for example, phenelzine [Nardil], tranylcypromine or [Parnate]) can result in greater depression of brain function as well as low blood pressure.
  • Because baclofen can increase blood sugar, doses of antidiabetic drugs may need to be adjusted when baclofen is started.

Flexeril drug interactions

  • Cyclobenzaprine is chemically related to the tricyclic class of antidepressants, for example, amitriptyline (Elavil, Endep), nortriptyline Pamelor). As such, it should not be taken with or within two weeks of any monoamine oxidase (MAO) inhibitor, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane). High fever, convulsions, and even death can occur when these drugs are used together.
  • Cyclobenzaprine interacts with other medications and drugs that slow the brain's processes, such as

Are baclofen and Flexeril safe to take if I am pregnant or breastfeeding?

Baclofen safety

  • The use of baclofen by pregnant women has not been evaluated.
  • Baclofen can be detected in the breast milk of mothers taking oral baclofen. No information is available on the presence of baclofen in the breast milk of mothers receiving baclofen intrathecally.

Flexeril safety

  • There are no adequate studies of cyclobenzaprine in pregnant women. However, studies in animals suggest no important effects on the fetus. Cyclobenzaprine therefore can be used in pregnancy if the physician feels that it is necessary.
  • It is not known whether cyclobenzaprine is secreted in milk. However, since it is related to the tricyclic antidepressants, some of which are excreted in breast milk, caution is advised in using this medication in women who are breastfeeding.

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Summary

Baclofen, brand names Gablofen, Lioresal, is a muscle relaxant prescribed for the treatment of skeletal muscle spasms, rigidity, muscle clonus, and pain caused by diseases such as multiple sclerosis (MS) and cystic fibrosis. Flexeril, generic name cyclobenzaprine, also is a muscle relaxant prescribed to treat acute, short-term muscle spasms and associated pain.

Baclofen and Flexeril have similar side effects, for example, confusion, drowsiness, dizziness, constipation, and nausea. Side effects of baclofen that are different from Flexeril include weakness, vomiting, low blood pressure, insomnia, and seizures. Side effects of Flexeril that are different from baclofen include dry mouth, fatigue, blurred vision, acid reflux, nervousness, and stomach or belly pain.

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Medically Reviewed on 2/8/2018
References
REFERENCE: FDA Prescribing Information.
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