Baclofen vs. Cyclobenzaprine: Similarities and Differences

Rosanna Sutherby, PharmD
·10 min read

Medically reviewed by Femi Aremu, PharmD

Baclofen and cyclobenzaprine are prescription skeletal muscle relaxants used to relieve muscle spasms due to certain muscular injuries or conditions.

The Food and Drug Administration (FDA) has approved baclofen to reduce muscle spasms due to multiple sclerosis or spinal cord injury. Cyclobenzaprine is approved to relieve muscle spasms due to muscle injuries.

Both medications come in orally administered (taken by mouth) tablets. However, baclofen is also available in other oral and injectable forms. Cyclobenzaprine is available as a generic and under the brand name Amrix, an extended-release form. Baclofen is sold under several brands, including Fleqsuvy, Lyvispah, and Ozobax DS.

Although both drugs are considered skeletal muscle relaxants, there are several notable differences between the two. This article will highlight the similarities and differences between baclofen and cyclobenzaprine.

<p>Eric BERACASSAT / Contributor / Getty Images</p>

Eric BERACASSAT / Contributor / Getty Images

What Is Baclofen?

Baclofen is a skeletal muscle relaxant approved by the FDA to relieve muscle spasms due to multiple sclerosis or spinal cord injury.

Baclofen is available in the following dosage forms:

  • Oral tablet

  • Oral suspension (a type of liquid)

  • Intrathecal injection (an injection into the cerebrospinal fluid)

The oral forms of baclofen are approved for use in adults and children ages 12 years and older. The intrathecal injection may be used in adults and children ages 4 years and older.

Baclofen is a generic medication. However, it's also available in the following brand-name forms:

  • Fleqsuvy oral suspension

  • Gablofen intrathecal injection

  • Lioresal intrathecal injection

  • Lyvispah oral granules

  • Ozobax DS oral solution (a type of liquid)

This article will focus on the baclofen dosage forms available as generics.

Baclofen Off-label Uses

Sometimes, healthcare providers may prescribe baclofen to treat conditions or at doses that differ from what the drug was initially approved for. This is called an off-label use.

Baclofen may be used off-label for the following goals:

How It Works

Baclofen acts on nerves in your spinal cord to help relax muscles. This results in fewer and less severe muscle spasms.

What Is Cyclobenzaprine?

Like baclofen, cyclobenzaprine is a prescription skeletal muscle relaxant. However, its uses and dosage forms differ somewhat from baclofen.

Flexeril was a brand name for the generic drug cyclobenzaprine oral tablet. However, the brand-name version is no longer available.

Cyclobenzaprine is also available as an extended-release oral capsule. It is available in a generic version and the brand-name Amrix.

This article will focus on the cyclobenzaprine oral tablet, the discontinued Flexeril's generic form.

Cyclobenzaprine oral tablet is used along with rest and physical therapy to reduce muscle spasms due to muscle injuries, such as muscle strains (a pulled muscle) or sprains (an injury to ligaments).

It's approved for use in adults and children ages 15 years and older.

Cyclobenzaprine Off-Label Uses

Cyclobenzaprine may be used off-label to treat the following:

  • Certain symptoms of post-traumatic stress disorder (PTSD) (a mental health disorder that arises after experiencing or witnessing a tragic event or series of events)

  • Myofascial pain (a long-term pain condition that involves muscles and the fascia, the thin tissue that covers and supports muscles)

  • Trouble sleeping due to fibromyalgia (a condition of widespread, chronic pain)

How It Works

Cyclobenzaprine does not work directly on the muscles. Instead, it works by slowing down activity in your central nervous system (CNS), which consists of your brain and spinal cord.

Researchers believe that your body may produce muscle spasms after an injury to prevent specific muscles from moving, thereby avoiding further damage to the area.

By slowing down activity in your CNS, cyclobenzaprine reduces signals from your brain that promote muscle spasms. This results in more relaxed muscles.

Baclofen vs. Cyclobenzaprine: Main Differences

The table below outlines key differences between baclofen and cyclobenzaprine.

 

Baclofen

Cyclobenzaprine 

Uses

Relieve muscle spasms due to multiple sclerosis or spinal cord injury

Relieve muscle spasms due to muscle injuries

Dosage forms

Oral tablet Oral suspension Intrathecal injection

Oral tablet

Dosage

Oral forms: 5 milligrams (mg) three times per day to 20 mg four times per day Injection: 90 micrograms (mcg) to 800 mcg per day

5 mg, 7.5 mg, or 10 mg three times per day

Precautions

Can take with monoamine oxidase inhibitors (MAOIs) and selective serotonin reuptake inhibitors (SSRIs) Caution advised with kidney conditions

Should not take with MAOIs or SSRIs Caution advised with liver conditions

Dosage: How to Take Baclofen and Cyclobenzaprine

Below are the recommended dosages for baclofen and cyclobenzaprine. Keep in mind that your healthcare provider will prescribe a dosage specific for your condition. It's important to follow their instructions carefully.

Baclofen Dosage

The dosage of baclofen varies based on the drug form you take or use.

Dosage for oral forms of baclofen

Oral forms of baclofen are typically taken three times daily. Your healthcare provider may start you at a low dose of 5 mg three times daily. If needed, they may gradually increase your dosage by 5 mg per dose every three days until you have the desired effect.

The maximum dose of oral forms of baclofen is 80 mg per day. If you take this 80 mg dose daily, your healthcare provider will likely recommend you take 20 mg four times a day.

Dosage for baclofen intrathecal injection

A healthcare provider must administer a Baclofen intrathecal injection. The injection is typically given in your back.

Before a baclofen intrathecal injection, your healthcare provider will give you a screening injection of 50 mcg and observe your response. Further screening doses may be given if the response is less than desired.

If this dose is safe and effective for you, your healthcare provider will adjust your dose, as follows, based on the cause and severity of your muscle spasms:

  • Dosage for muscle spasms due to spinal cord injuries: 300 mcg per day to 800 mcg per day

  • Dosage for muscle spasms due to multiple sclerosis: 90 mcg per day to 700 mcg per day

Baclofen injection and oral forms may be used long term.

Cyclobenzaprine Dosage

Like oral forms of baclofen, the cyclobenzaprine tablet is also taken three times per day.

Your healthcare provider will likely have you start taking 5 mg of cyclobenzaprine three times per day. If needed, they may increase your dose to 7.5 mg or 10 mg three times daily.

Cyclobenzaprine is not typically used long-term. The recommended length of treatment is two to three weeks.

Can You Take Baclofen and Cyclobenzaprine Together?

It's best not to take baclofen and cyclobenzaprine together. Both baclofen and cyclobenzaprine can slow down activity in your CNS. This may lead to side effects such as sleepiness, dizziness, or fatigue.

Taking both medications together may increase your risk of side effects or worsen them.

If your healthcare provider prescribes baclofen and cyclobenzaprine together, they may prescribe a lower dose of either medication. They'll also monitor you for signs of increased side effects.

Which Is More Effective?

Which muscle relaxant, baclofen or cyclobenzaprine, is more effective depends on factors such as the condition you're treating.

Baclofen is considered a first choice for treating muscle spasms caused by spinal cord injury. Studies have shown that baclofen is more effective at reducing muscle spasms and improving muscle tone than placebo (inactive medication) in up to 72% of study participants.

In studies of people taking cyclobenzaprine for back pain, participants who took cyclobenzaprine were five times more likely to have improvement in symptoms, including muscle spasms, compared with those taking placebo.

Safety and Side Effects

Like all medications, baclofen and cyclobenzaprine may cause side effects in some people. Most side effects of these medications are mild and don't require medical attention.

However, if you experience very bothersome or severe side effects from baclofen or cyclobenzaprine, inform your healthcare provider immediately. They may adjust your dosage or recommend a different treatment for your condition.

Common Side Effects of Baclofen

Common side effects of baclofen include:

Common Side Effects of Cyclobenzaprine

Some common side effects of cyclobenzaprine include:

In rare cases, baclofen and cyclobenzaprine may cause severe side effects.

Severe Side Effects of Baclofen

Severe side effects of baclofen can include:

Severe Side Effects of Cyclobenzaprine

Severe side effects of cyclobenzaprine can include:

Shared Side Effects

Baclofen and cyclobenzaprine may have different side effects, but some are similar. Side effects that are shared by the two drugs include:

  • Sleepiness

  • Dizziness

  • Fatigue

  • Fainting

Precautions

Before starting treatment with baclofen or cyclobenzaprine, it's important to be aware of precautions if your healthcare provider prescribes either of these medications.

Precautions include:

  • Do not stop taking baclofen suddenly. Doing so can increase your risk of hallucinations and seizures. If you and your healthcare provider decide you should stop taking baclofen, your provider will gradually decrease your dose to lower your risk of having seizures or hallucinations.

  • If you have a kidney condition, your healthcare provider may prescribe a lower baclofen dose.

  • You should not take cyclobenzaprine if you have had a recent heart attack or have other heart conditions, such as irregular heart rhythm or congestive heart failure (CHF).

  • You should not take cyclobenzaprine if you have hyperthyroidism (an overactive thyroid gland).

  • If you have a liver condition, your healthcare provider may prescribe a lower dose of cyclobenzaprine.

Do Baclofen and Cyclobenzaprine Have Similar Drug Interactions?

Because baclofen and cyclobenzaprine both slow down the activity in CNS, they have some similar drug interactions.

For example, both baclofen and cyclobenzaprine can interact with alcohol and opioid pain medication, such as:

In addition, cyclobenzaprine has interactions with the following types of drugs:

Baclofen does not interact with MAOIs or SSRIs.

It's important to let your healthcare provider know all the medications you take before you start baclofen or cyclobenzaprine treatment.

These lists do not include all possible drug interactions for baclofen or cyclobenzaprine. If you have questions about drug interactions, your pharmacist or other healthcare provider can help.

Summary

Baclofen and cyclobenzaprine are both skeletal muscle relaxants that are FDA-approved to relieve muscle spasms due to certain nerve or spinal cord-related conditions or muscle injuries. Differences between the two include their uses, dosages and dosage forms, and ages for approved uses.

Although both drugs are muscle relaxants, baclofen is used for muscle spasms related to multiple sclerosis or spinal cord injury. Cyclobenzaprine is more often used to relieve muscle spasms due to muscle injuries.

Baclofen is available in several dosage forms, including an oral tablet and intrathecal injection. Cyclobenzaprine only comes as an oral tablet. Baclofen oral forms are approved for use in adults and children 12 years and older. The injection may be used in adults and children as young as 4 years of age.

Cyclobenzaprine oral tablet is approved for use in adults and children ages 15 years and older.

Both baclofen and cyclobenzaprine have some similar as well as different side effects and drug interactions. Talk with your healthcare provider to learn which medication is right for you.

Read the original article on Verywell Health.