Baclofen Mechanism of Action: How Does Lioresal Work?

Last Updated: June 3, 2020

Authored by Sharon Levy, MD, MPH

Muscles relaxants such as Baclofen(Lioresal) have been widely used over the years. Baclofen pills are used for treating spasticity, muscles spasms and are also helpful in treating alcohol use disorder. Most patients who are planning to undergo Lioresal treatment or even have already been prescribed to Baclofen do not know Baclofen mechanism of action. Sometimes they don’t have any idea on how this medication works in their bodies either. Studying how Baclofen works is helpful to make the treatment process more effective and can even help to prevent an overdose.

Understanding How Baclofen works

MD is studying Baclofen mechanism of actionCurrently, the precise Baclofen mechanism of action is not fully known. According to the study by the U.S. Federal Science, it is indicated that it is a GABA-B receptor agonist. Although this is somewhat true, however, there is no evidence that the effects on GABA systems by Lioresal are involved in the results of its clinical effects.
Gablofen is proven useful on the spinal site of action and is widely used as an antispastic agent. This is one of the points, where Baclofen is similar to Flexeril. Compared to other antispastic agents, it’s pharmacological properties, and mechanism of actions differ.
GABA-B receptors affect and interact with neurotransmitter systems and signal transduction pathways. Mechanism of action of the medication also employs an antinociceptive effect. This clinical significance deserves further study and research to clarify its result.
According to Lioresal mechanism of action, it reduces the level of activity of the monosynaptic and polysynaptic reflex transmission by a variety of actions, in a similar way to some alternatives of Baclofen, and also the simulation of GABA-B receptors. This results in the inhibition of aspartate and glutamate release which contributes or triggers spasticity and pain.

How Long Does Baclofen Take to Work?

Noticing the effect of this drug varies within individuals. For example, one can be prescribed 10mg of Baclofen three times a day, but won’t feel the effects for days, others can be prescribed that same dose but will feel the effect of the drugs immediately. Due to its mechanism of action, studies and reviews from users, improvement starts to show from two days up to two weeks of the initial prescription time as far as the patient continuously follow the treatment plan.

Pharmacodynamics of Baclofen

When a patient is diagnosed with neurological diseases closely related to the spasm of skeletal muscles, they are administered Lioresal pills or Medtronic baclofen pump which due to Baclofen moa the clinical effects occur. This can have effects on muscles contractions providing significant relief from automatism, clonus as well as painful spasms. Lioresal provides its users with improved mobility and increased level of independence while facilitating both active and passive physiotherapy. The medication increases the secretion of gastric acid as well.

Doctor is looking in the medical bookThe activation of the GABA-B receptor may produce protective neurological effects in other words Baclofen can get one high. The drug also has anti-inflammatory properties which can be useful in the study of addiction treatment. The study conducted by The Acute Care Nurse Practitioners shows that GABA-B receptors have roles in memory storage and retrieval, anxiety, motivation, reward, and even mood as well.

Neuroimaging studies conducted by the National Center for Biotechnology Information also indicates that drugs like Baclofen cause region-specific alterations in brain activity. Due to these reasons, patients who use Baclofen for a long time should not stop immediately to avoid having Baclofen withdrawal syndrome.

How Does Baclofen Works in a Body System?


Absorption of Baclofen tablets occurs rapidly and almost entirely from the gastrointestinal region. This process may be wholly dependent on the dose, and it is reduced with increases in doses. Patients also need to keep it in mind that the intake of the drug can cause several side effects.

If the medication is admitted directly into the subarachnoid space or the spinal canal, as Gablofen injections, it reaches the Cerebrospinal Fluid (CSF) to achieve an effective CSF concentration, its resulting plasma concentration is 100 times less than concentrations when it is administered orally.


Doctor is studying Baclofen metabolism processNearly 15% of the administered dose of Lioresal is deaminated in the liver during metabolism. In a study using radiolabeled Baclofen, it was found out that about 85% was passed as feces and urine. After the deamination of the medicine, 3-(p-chlorophenyl)-4-hydroxybutyric acid, and the y-hydroxy metabolite are produced.

Because the drug is partially metabolized in the liver, it is advisable that users with questionable liver function should be monitored over time during the usage of this drug.


Lioresal route of elimination from the body is extensive and very rapid. The drug is excreted primarily by the kidney as unchanged substance. About 70-80% of a single dose is estimated in the urine as unchanged substance. The rest is excreted unchanged as feces or as metabolites.

Excretion of Baclofen is complete within 72 hours after the intake of the drug.

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Published on: March 4th, 2019

Updated on: June 3rd, 2020

About Author

Sharon Levy, MD, MPH

After successful graduation from Boston University, MA, Sharon gained a Master’s degree in Public Health. Since then, Sharon devoted herself entirely to the medical niche. Sharon Levy is also a certified addiction recovery coach.


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