Key takeaways:
Baclofen (Ozobax DS, Fleqsuvy) and Flexeril (cyclobenzaprine) are prescription-only medications that treat muscle spasms. Baclofen is FDA approved for muscle spasms from multiple sclerosis or spinal cord injuries, while Flexeril treats those from certain musculoskeletal conditions.
Baclofen and Flexeril both have side effects and interactions to be aware of. Keep a current medication list available for your prescriber and pharmacist. They can check for any interactions with either medication.
Baclofen and Flexeril are both available as lower-cost generics. GoodRx could help you save over 80% off the average retail price of these medications at certain pharmacies.
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Many people experience muscle cramps, or muscle spasms, every now and then. They typically occur when we overuse or injure our muscles. While these cramps can be painful, they usually last for only a few minutes.
Certain health conditions cause or contribute to muscle spasms, too, though. And these frequent muscle spasms can be tough to deal with. If home treatments — such as stretching and over-the-counter (OTC) pain relievers — aren’t doing the trick, there are prescription muscle relaxers that can help relieve your symptoms.
Two common muscle relaxers are baclofen (Ozobax DS, Fleqsuvy) and Flexeril (cyclobenzaprine). These medications are routinely filled at pharmacies across the country by people experiencing muscle spasms. But they’re prescribed for different reasons.
Here, we’ll compare baclofen versus Flexeril on five key features — what they treat, how effective they are, and more.
Good to know: Flexeril is a brand-name medication that’s no longer on the market. But generic versions are still available. We refer to cyclobenzaprine as brand-name Flexeril in this article since many people are familiar with the medication this way.
1. Baclofen and Flexeril both treat muscle spasms, but they’re approved for different underlying causes
Baclofen and Flexeril are both prescription muscle relaxers. The main differences between baclofen and Flexeril boil down to what they treat.
Oral baclofen is FDA approved to manage muscle spasms in people living with multiple sclerosis or a spinal cord injury. It comes as tablets, an oral solution (Ozobax DS), and an oral suspension (Fleqsuvy). Oral baclofen is approved for adults and kids ages 12 years and older.
An injectable version of baclofen, called baclofen intrathecal (Gablofen, Lioresal) is also available. This is a treatment option for severe muscle spasms. It’s approved for adults and kids ages 4 years and older who don’t respond to oral baclofen or can’t tolerate the side effects. It’s administered through a pump that delivers the medication to the spine.
Flexeril treats muscle spasms and pain caused by musculoskeletal conditions, such as sprains and strains. It’s only approved for short-term use (2 to 3 weeks at a time) in adults and teens ages 15 years and older. Cyclobenzaprine extended-release (ER) capsules, which are available under the brand name Amrix, treat muscle spasms in adults.
Tonmya is the newest form of cyclobenzaprine. It comes as sublingual tablets that dissolve under the tongue. It’s approved to treat fibromyalgia in adults, though, not muscle spasms.
How do baclofen and Flexeril work for muscle spasms?
Baclofen and Flexeril work differently to relieve muscle spasms.
Baclofen is an antispastic medication that acts on specific receptors (chemical binding sites) in the central nervous system (CNS) to reduce excessive nerve activity. By calming these signals, it helps decrease the frequency and intensity of muscle spasms.
Flexeril, by contrast, is an antispasmodic medication. It also works on the CNS, but it mostly acts at the brainstem, rather than directly on skeletal muscles. Because it’s not an antispastic medication, Flexeril isn’t effective for muscle spasms caused by conditions like multiple sclerosis.
2. Baclofen and Flexeril’s recommended dosages and lengths of use slightly differ
Overall, baclofen and Flexeril are administered in similar ways. Here’s a quick summary of how baclofen and Flexeril oral tablet dosages compare and contrast.
| Baclofen | Flexeril | |
|---|---|---|
| Tablet doses |
|
|
| Typical starting dosage | 5 mg by mouth 3 times daily | 5 mg by mouth 3 times daily |
| Usual maximum daily dose | 20 mg by mouth 4 times daily | 10 mg by mouth 3 times daily |
| Recommended duration of use | Long term, or until you and your healthcare team decide it’s time to slowly stop the medication | 2-3 weeks |
| Does kidney or liver function affect dosages? | Yes, kidney function is a factor. | Yes, liver function is a factor. |
3. Their effectiveness differs, too
For muscle spasticity conditions — especially spinal cord injuries — experts consider baclofen a possible first-choice option. Clinical trials showed that oral baclofen improved muscle tone in up to 72% of study participants, compared with up to 17% of participants who saw improvement with a placebo (pill with no medication). And research shows baclofen intrathecal may be more effective than oral baclofen for spinal cord injuries.
For muscle spasms caused by muscle and bone issues, Flexeril is considered moderately effective. Some studies have suggested that people taking Flexeril are 5 times more likely than those taking a placebo to experience improvement in pain-related muscle symptoms within 2 weeks.
4. Baclofen and Flexeril each come with their own set of side effects
Like all medications, baclofen and Flexeril have a number of side effects to keep in mind. Some are common to both medications, while others are more unique to one. Side effects also vary by dose and dosage form.
Check out the table below for a list of common, but not all, baclofen and Flexeril side effects. The percentages reflect the portion of people who experienced the side effects in clinical trials.
Side effect | ||
|---|---|---|
Drowsiness | 10-63% | 29% |
Dry mouth | Rare | 21% |
Dizziness | 5-15% | 1-3% |
Weakness | 5-15% | Less than 1% |
Headaches | 4-8% | 5% |
Fatigue | 2-4% | 6% |
Baclofen has serious risks that differ from Flexeril’s
A number of rare but serious side effects are also possible with baclofen. If you experience serious side effects, such as the ones below, get medical help right away.
Sudden withdrawal symptoms
Abruptly stopping baclofen can cause severe withdrawal symptoms. This may include fever, nausea, and weakness. Seizures and unusual behavior are also possible. If you would like to stop taking baclofen, talk with your healthcare professional first. They can help you slowly stop taking the medication over time to prevent withdrawal side effects.
Withdrawal symptoms in newborns
If you’re taking baclofen during pregnancy, your healthcare professional may want you to slowly stop the medication before your delivery date to limit withdrawal side effects in your baby. This is because, within hours to days after delivery, newborns can experience withdrawal symptoms such as rigid muscles, tremors, and seizures.
The benefits of continuing to take baclofen during pregnancy may outweigh the risks, though. In this case, your healthcare team may recommend administering baclofen to your newborn after birth, followed by slowly lowering the dosage to prevent withdrawal.
Good to know: Research shows intrathecal baclofen may be a safer option during pregnancy. It typically produces lower blood levels in the body than oral baclofen. This means it’s less likely that a newborn will have been exposed to the medication.
Seizures
If you’re living with epilepsy, baclofen can raise your chances of experiencing seizures. Your healthcare team may want to closely monitor your brain waves over time to manage this risk.
Flexeril has serious risks that differ from baclofen’s
For Flexeril, seek immediate medical attention if you experience symptoms of serotonin syndrome or any heart-related side effects.
Serotonin syndrome
Serotonin is a chemical in the brain that helps with mood. But too much serotonin can be harmful. Serotonin syndrome is a rare but potentially life-threatening condition. Symptoms may include confusion, sweating, and seizures.
The risk of serotonin syndrome is higher when you take Flexeril with other medications that raise serotonin levels. Selective serotonin reuptake inhibitors (SSRIs), such as sertraline (Zoloft), are a common example.
If you’re concerned about serotonin syndrome, speak to your prescriber as soon as possible.
Heart-related side effects
While rare, Flexeril may raise your risk for heart-related side effects. If you have a heart condition like an arrhythmia (irregular heartbeat), it’s best to avoid Flexeril out of caution. Arrhythmias have been reported in some people taking Flexeril. Symptoms may include skipped heartbeats, dizziness, and shortness of breath.
5. Baclofen and Flexeril have overlapping as well as unique interactions
Certain medications and substances don’t mix well with baclofen and Flexeril.
In general, avoid taking baclofen or Flexeril with alcohol, opioid medications, or benzodiazepines. Any of these combinations can worsen the risk of excessive drowsiness or sleepiness.
You should also avoid taking Flexeril within 2 weeks of a monoamine oxidase inhibitor (MAOI). Combining Flexeril and MAOIs raises the risk of serotonin syndrome. It can also cause MAOI toxicity, with symptoms that include high blood pressure and fever. Examples of MAOIs include rasagiline (Azilect) and selegiline (Emsam).
Flexeril also interacts with the pain medication tramadol (ConZip). Combining these two medications can raise your chances of experiencing a seizure.
Good to know: This isn’t a complete summary of baclofen and Flexeril interactions. Keep a current list of your prescription and OTC medications handy. Your prescriber and pharmacist can screen for any possible interactions before you start taking baclofen or Flexeril.
Can you take baclofen and Flexeril together for muscle spasms?
No, since baclofen and Flexeril treat muscle spasms due to different medical conditions, they’re not typically taken together. Plus, both of these medications can cause drowsiness and dizziness. It’s best not to combine them, if possible, to avoid an elevated risk of side effects.
How to save on baclofen and Flexeril
Baclofen and cyclobenzaprine are both available as lower-cost generics. GoodRx can help you navigate ways to save on your prescription. That includes GoodRx coupons, which could help you save over 80% off the average retail price of generic baclofen or cyclobenzaprine.
Thirty tablets of generic baclofen 5 mg may cost as low as $15.00 with a free GoodRx discount at certain pharmacies. The same quantity and dose of cyclobenzaprine may cost as low as $9.30 with a free GoodRx discount.
The bottom line
Baclofen (Ozobax DS, Fleqsuvy) is a go-to choice for treating muscle spasms from multiple sclerosis or spinal cord injuries. Flexeril (cyclobenzaprine) is a moderately effective option for muscle spasms due to muscle or bone problems. These medications have side effects, such as drowsiness and dizziness, you should be aware of. They also interact with certain medications and substances like opioids and alcohol. If you have questions or concerns about either medication, reach out to your pharmacist or prescriber.
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