Baclofen | Amazing Uses, Mechanism of Action, Side Effects
Written By Kobi Nathan, Pharm.D., M.Ed., CDP, BCGP, AGSF
Sleep Disorders
April 12, 2023

Baclofen is a medication primarily prescribed to treat muscle spasticity and spasms caused by various neurological conditions.

It acts as a muscle relaxant by inhibiting the release of neurotransmitters, which are responsible for transmitting messages between nerves in the body.

Baclofen’s mechanism of action is unique compared to other muscle relaxants, making it a popular choice for individuals with chronic spasticity.

While baclofen is generally well-tolerated, it can cause negative medication effects such as drowsiness, dizziness, and weakness.

It is important to talk to a healthcare provider before starting or stopping taking baclofen, and to follow the prescribed dosage carefully.

This article will provide a detailed analysis of the uses, mechanism of action, side effects, and other important information about baclofen.

What are the brand names for baclofen?

  • Lioreal.
  • Ozobax.
  • Gablofen.
  • Fleqsuvy.
  • Lyvispah.

What is Baclofen Used For?

In 1962, Swiss chemist Heinrich Keberle developed Baclofen with the goal of creating a medication for epilepsy.

Although it didn’t work effectively for epilepsy, researchers found that Baclofen could help reduce spasticity in some patients.

As a result, the drug was reintroduced in 1971 and later approved by the US Food and Drug Administration (FDA) for this new indication in 1977.

Baclofen FDA-approved indications

Today, baclofen is used to treat muscle spasms, stiffness, and associated pain (spasticity) related to:

  • Clonus.
  • Concomitant pain (co-existing pain from spasms).
  • Cerebral palsy.
  • Spinal cord injuries.
  • Multiple sclerosis.
  • Other Neurological Disorders.

Most of the medical problems mentioned above can be treated with oral baclofen tablets and suspensions.

However, these oral formulations cannot effectively manage certain conditions and may require a stronger, more direct approach, such as intrathecal administration.

Let’s discuss below:

Baclofen Pump

A baclofen pump, also known as an intrathecal pump, is a device that delivers baclofen directly into the spinal fluid.

This method is typically used for patients with severe spasticity who do not respond well to oral baclofen or experience intolerable side effects.

The medication can also be administered intrathecally to manage spasticity of cerebral origins, such as traumatic brain injury (TBIs) or severe spasticity of spinal cord origin that is unresponsive to treatment with maximum doses of oral baclofen, tizanidine, and/or dantrolene.

Uncontrollable muscle spasms can be incredibly debilitating and painful.

I believe the best way to describe these spasms’ negative effects on a person’s life is to show you how positively life-changing using a baclofen pump can be.

The video below shows a quadriplegic individual after baclofen pump surgery:



In my clinical work serving patients recovering from traumatic brain and spinal cord injuries, I have seen first-hand what the intrathecal administration of baclofen can do to improve my patients’ quality of life.

However, getting the dose just right so that the therapeutic outcomes are maximized while the sedating side effects are minimized takes expertise, patience, and very close monitoring and follow-up.

Only a qualified medical specialist well-trained in prescribing and managing intrathecal baclofen pumps should be making these decisions.

If you want to learn more about intrathecal baclofen pumps, read my detailed article here.

Off-labeled Uses

Baclofen has been shown to treat some forms of hiccups, trigeminal neuralgia, and even alcohol withdrawal.

Mechanism of Action of Baclofen

To understand how baclofen therapy works, it’s important to know about a key substance in our brain called GABA.

GABA (gamma-aminobutyric acid) is a natural chemical found in our brain, which helps to keep our nerve cells’ activity under control.

It does this by “calming down” the cells, making them less likely to become overactive and send too many signals.

This is important because when nerve cells become overactive, they can cause muscle stiffness and spasms.

Baclofen works by imitating the action of GABA in our brain.

Specifically, it targets a type of GABA receptor called GABA-B.

When baclofen binds to these GABA-B receptors, it helps to reduce the activity of nerve cells, just like GABA does naturally.

As a result, the nerve cells send fewer signals, which helps to relax the muscles and reduce muscle stiffness and spasms.

Is Baclofen a Controlled Substance?

Baclofen is not considered a controlled substance in the United States.

According to the DEA’s list of controlled substances, it is not classified under any of the five schedules.

How Long Does it Take for Baclofen to Work?

The onset of action for baclofen tablets varies among individuals, but it is rapidly absorbed and typically begins to work within 30 minutes to an hour following oral administration.

Peak blood concentrations are achieved within two hours.

For some patients, the medication may take up to 2 weeks to reach its full therapeutic effect.

How Long Does Baclofen Stay in Your System?

Baclofen’s half-life ranges between 2-4 hours and is primarily excreted through the kidneys.

Complete elimination from the body may take up to 20 hours for most individuals, but this can vary based on factors such as age, kidney function, and other medications being taken.

Toxicity and side effects from baclofen 

The effectiveness and safety of baclofen have been well-established for years.

That said, it can cause a variety of possible side effects, including:

  • Drowsiness.
  • Dizziness.
  • Weakness.
  • Headache.
  • Tremor.
  • Urinary frequency.
  • Urinary retention.
  • Nasal congestion.
  • Nausea.
  • Constipation.
  • Depression.
  • Hallucination.
  • Tinnitus.
  • And many others.

These common adverse reactions are generally mild and may improve over time.

However, severe side effects, such as seizures, hallucinations, or difficulty breathing, may also occur.

Consult your doctor or pharmacist immediately if you experience any severe side effects.

You may also report side effects to FDA at 1-800-FDA-1088.

Baclofen adverse effects in elderly

Elderly patients may be more susceptible to certain side effects of baclofen, such as drowsiness, dizziness, and confusion.

In older adults, one single dose of baclofen takes longer to get absorbed, stay in the system, and get eliminated.

So, great care must be taken to ensure that the proper dose, duration of treatment, and monitoring are done for your older loved ones.

Ask your doctor to closely monitor you for these side effects and adjust the dosage accordingly to keep you pain-free and free from negative drug effects.

Baclofen dosage

Baclofen dosage varies depending on the patient’s age, weight, and the severity of their condition.

It is important to take baclofen exactly as prescribed by your doctor.

If you forget to take a dose that is too close to your next dose, don’t double up and take another one.

Just skip the missed dose and return to your regular schedule immediately.

If the label on your baclofen prescription bottle shows that it is expired, please do not take the medication.

It should be discarded appropriately and responsibly.

Depending on where you live, you may be able to drop off your expired medication at your local pharmacy, fire station, or police department.

In my article, “Can I take expired baclofen?” I discuss the reasons in detail.

If you want to read how baclofen compares to tizanidine, another commonly used muscle relaxant, read my article here.

Baclofen 10 mg

The 10 mg dose is a common starting point for many patients.

It is usually taken three times a day, and the dosage may be gradually increased under the supervision of your doctor.

Baclofen 20 mg

The 20 mg dose is generally prescribed for patients with more severe muscle spasticity.

It is also typically taken three times daily, with the dosage adjusted based on the patient’s response to the medication.

The total maximum dose for oral baclofen is 80 mg daily.

However, it is not uncommon to see patients prescribed more than this amount to manage their symptoms.

Almost always, a neurologist or rehabilitation medicine specialist makes these types of decisions when the doses need to be increased beyond recommended doses.

Baclofen toxicity

Baclofen overdose symptoms

Baclofen overdose may include:

  • Severe drowsiness.
  • Muscle weakness.
  • Lightheadedness.
  • Slow or shallow breathing.
  • Seizures.
  • Loss of consciousness.

If you suspect a baclofen overdose, seek immediate medical attention.

Baclofen withdrawal symptoms

You should not stop taking baclofen abruptly.

Doing so can lead to withdrawal symptoms, which may include:

  • Anxiety.
  • Agitation.
  • Altered mental status.
  • Insomnia.
  • Muscle spasms.
  • Seizures.
  • High fever.

To prevent abrupt withdrawal symptoms, baclofen should be gradually tapered off under the supervision of a healthcare professional.

Baclofen drug interactions

Baclofen may interact with other medications, leading to increased side effects or reduced effectiveness.

Some potential interactions include:

It is essential to inform your healthcare provider of all medications you are taking to avoid potential interactions.

Baclofen vs Flexeril: Comparing muscle relaxants

Baclofen and Flexeril (cyclobenzaprine) are both muscle relaxants, but they have different mechanisms of action, indications, and side effect profiles.

The choice between the two medications depends on the specific patient’s needs, type of pain, and the physician’s recommendations.

This section provides a detailed comparison of Baclofen and Flexeril.

Baclofen vs. Flexeril: Mechanism of action

As I mentioned, baclofen acts as a receptor agonist on GABA-B receptors in the central nervous system, reducing the release of excitatory neurotransmitters.

This results in a decrease in muscle spasticity and stiffness.

In contrast, cyclobenzaprine primarily targets skeletal muscles and works by inhibiting the transmission of nerve impulses in the central nervous system, leading to muscle relaxation.

Baclofen vs. Flexeril: Indications

Baclofen is primarily prescribed for treating muscle spasms and stiffness associated with neurological conditions such as spinal cord injuries, multiple sclerosis, and other spinal cord lesions.

On the other hand, Flexeril is mainly used for short-term relief of muscle spasms associated with acute, painful musculoskeletal conditions, such as lower back or neck pain.

Baclofen vs. Flexeril: Adverse effects

Both Baclofen and Flexeril have similar side effects, including drowsiness, dizziness, and dry mouth.

However, Baclofen may also cause weakness, nausea, and constipation, while Flexeril can lead to headaches, blurred vision, and confusion.

It is essential for patients to be aware of these potential side effects and to consult their healthcare provider if they experience any severe or persistent symptoms.


Baclofen is contraindicated in patients with a known hypersensitivity to the drug, and caution should be exercised in those with impaired kidney function, seizures, or a history of stroke.

Flexeril is contraindicated in patients with a recent history of heart attack, heart block, or arrhythmias and those with a known hypersensitivity to the drug or tricyclic antidepressants.

Drug interactions

Baclofen may interact with medications such as alcohol, antidepressants, antihistamines, opioids, other muscle relaxants, and sleep aids.

Flexeril has the potential to interact with monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, and other medications that may cause drowsiness.

However, in certain cases where baclofen alone may not be enough to provide relief, tizanidine may be added as a combination therapy. I discuss this in detail in my article baclofen vs tizanidine.

Duration of treatment

Baclofen is generally used for the long-term management of muscle spasticity and stiffness associated with neurological conditions.

In contrast, Flexeril is typically prescribed for short-term use, with treatment duration usually not exceeding 2 to 3 weeks.

Expired baclofen

You should not take expired baclofen. To learn more, read my article here.

Does baclofen show up on a drug test?

Baclofen does not typically appear on standard drug tests, as it is not a controlled substance.

However, specialized testing can be performed to detect its presence if necessary.

Key Takeaways

Baclofen and Flexeril are both muscle relaxants with different mechanisms of action, indications, and side effect profiles.

The choice between the two medications depends on your needs and your doctor’s recommendations.

You should discuss your medical history, symptoms, and medication use with your healthcare provider to determine the most appropriate treatment option.


Baclofen is an effective medication for managing muscle spasms and stiffness in patients with various neurological disorders.

Understanding its mechanism of action, potential adverse effects, and interactions with other medications is crucial to ensure safe and effective use.

Always consult a healthcare professional before starting or stopping any medication, and follow their guidance for dosage and administration.

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