Robaxin vs. Flexeril: Differences, similarities, and which is better for you

In this article:

• What are the main differences between Robaxin and Flexeril?
• Conditions treated by Robaxin and Flexeril
• Efficiacy
• Cost and coverage
• Side effects
• Interactions
• Warnings
• FAQs

In this article

• What are the main differences between Robaxin and Flexeril?
• Conditions treated by Robaxin and Flexeril
• Efficiacy
• Cost and coverage
• Side effects
• Interactions
• Warnings
• FAQs

Muscle relaxants are some of the most commonly prescribed medications to treat back pain and other strains or sprains. Robaxin (methocarbamol) and Flexeril (cyclobenzaprine) are examples of skeletal muscle relaxants (SMRs) that your healthcare provider may prescribe if you experience muscle pain. 

Both Robaxin and Flexeril work in similar ways by acting on the central nervous system (CNS). Further classified as antispasmodic agents, Robaxin and Flexeril are effective for treating acute, painful musculoskeletal conditions that cause discomfort and muscle spasms. They also have similar side effects, such as drowsiness and dizziness. Healthcare providers will typically prescribe one of these prescription medications along with other measures such as rest and physical therapy, and sometimes other medication, such as prescription or over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs).

What are the main differences between Robaxin and Flexeril?

Robaxin

Robaxin, known by its generic name methocarbamol, was released on the market in the 1960s. While its exact mechanism of action is unknown, methocarbamol is believed to relieve discomfort through its sedative effects. It does not directly affect muscle contractions.

Methocarbamol is available as a generic medication in 500 mg or 750 mg oral tablets. The brand name Robaxin is available in injection form but not in oral form. 

Flexeril

The FDA initially approved Flexeril in the 1970s. It primarily works on the brain stem and spinal cord in the CNS, which helps reduce motor activity. Flexeril is also structurally similar to tricyclic antidepressants and has similar side effects, such as dry mouth and sedation.   

Flexeril is commonly known by its generic name, cyclobenzaprine. The brand name has been discontinued. However, cyclobenzaprine is available in another brand name, Amrix (extended-release capsules).  

RELATED: Learn about Cyclobenzaprine 

Main differences between Robaxin and Flexeril
	Robaxin	Flexeril
Drug class	Muscle relaxant Antispasmodic agent	Muscle relaxant Antispasmodic agent
Brand/generic status	Generic oral form is available	Generic available;  Brand name Flexeril has been discontinued in the US.  Amrix is a brand-name,  extended-release formulation of cyclobenzaprine.
What is the generic name?	Methocarbamol	Cyclobenzaprine
What form(s) does the drug come in?	Oral tablet Injection	Oral tablet Oral extended-release capsule
What is the standard dosage?	Initial dosage: 1500 mg 4 times daily Maintenance dosage: 1000 mg 4 times daily, 1500 mg 3 times daily, or 750 mg every 4 hours	Immediate-release tablets: 5 mg three times daily. Dose may be increased to 10 mg 3 times daily. Extended-release capsules: 15 mg once daily. Dose may be increased to 30 mg once daily.
How long is the typical treatment?	Short-term or long-term treatment as directed by your doctor	Up to 2 or 3 weeks
Who typically uses the medication?	Adults and young adults ages 16 years or older	Adults and young adults ages 15 years or older

Conditions treated by Robaxin and Flexeril

Robaxin and Flexeril are both FDA-approved to relieve discomfort associated with acute, painful musculoskeletal conditions. They are generally prescribed along with other measures, such as rest and physical therapy. Methocarbamol can also be used in combination with other medicines to treat tetanus. Cyclobenzaprine is sometimes prescribed off-label (for a non-FDA-approved use) for fibromyalgia. 

Robaxin

• Acute, painful musculoskeletal conditions
• Tetanus (along with other medicine)
• Off-label for acute or chronic low back pain, arthritis, fibromyalgia, rib fractures, myofascial pain (a long-term muscle pain condition), and other conditions

Flexeril

• Acute, painful musculoskeletal conditions
• Off-label for fibromyalgia and myofascial pain

Is Robaxin or Flexeril more effective?

Robaxin and Flexeril are effective treatments for treating musculoskeletal pain and muscle spasms. The more effective drug is the one that works best for your specific case. 

Guidelines note that muscle relaxants are widely used, but they are not proven to be better than Tylenol (acetaminophen) or nonsteroidal anti-inflammatory drugs (NSAIDs) for low back pain. Research supports using muscle relaxants for short-term use when other treatments have not worked. Although cyclobenzaprine is the most studied muscle relaxant and has shown to be effective, studies have compared the various muscle relaxants and have not found one to be better than another. Because cyclobenzaprine has a sedative effect, people who have trouble sleeping due to muscle spasms may benefit from this medicine. Methocarbamol is less sedating, but there is limited evidence of its effectiveness. All muscle relaxants cause dizziness and drowsiness. 

Consult a healthcare professional for medical advice to find the best treatment options for you. After a complete assessment from a healthcare provider, one drug may be preferred depending on your overall medical history.

Coverage and cost comparison of Robaxin vs. Flexeril

Methocarbamol tablets are usually covered by Medicare and insurance plans. Methocarbamol tablets can be purchased at a retail cost of $31. A SingleCare discount card can lower this price to around $5 at a participating pharmacy.  

Cyclobenzaprine has a higher retail cost of $53, compared to methocarbamol. Generic cyclobenzaprine tablets are often covered by Medicare and insurance plans. If you don’t have insurance, you can use a SingleCare discount card to reduce this cost to about $5, depending on your pharmacy. Even if you do have insurance, it may be a good idea to find out if you can get a cheaper price on muscle relaxants by using a SingleCare discount instead. 

	Robaxin	Flexeril
Typically covered by insurance?	Yes (generic)	Yes (generic)
Typically covered by Medicare?	Yes (generic)	Yes (generic)
Standard dosage	500 mg tablets (quantity of 30)	10 mg tablets (quantity of 30)
Typical Medicare copay	$0–$20	$0–$20
SingleCare cost	$5+	$5+

Common side effects of Robaxin vs. Flexeril

 Common side effects of Robaxin include:

• Drowsiness
• Dizziness
• Stomach upset
• Blurry vision
• Fever 
• Discoloration of urine

Common side effects of Flexeril include:

• Dry mouth 
• Dizziness
• Stomach problems like nausea, constipation, or heartburn
• Tiredness 

More serious side effects of Robaxin and Flexeril include hypersensitivity reactions. These allergic reactions can manifest as trouble breathing, severe rash, and swelling. Seek immediate medical attention if you experience these adverse effects. 

Drug interactions of Robaxin vs. Flexeril

Before taking Robaxin or Flexeril, tell your healthcare provider about all the medicines you take, including prescription and OTC drugs, vitamins, and supplements. 

Robaxin interactions include the following:

• Alcohol
• Pyridostigmine bromide
• Drugs that are central nervous system (CNS) depressants, such as sleep aids, anxiety medicines, opioid pain medicines, or phenobarbital

Flexeril interactions include the following:

• Alcohol
• Drugs that increase serotonin levels, such as SSRI antidepressants, SNRI antidepressants, tricyclic antidepressants, bupropion, or monoamine oxidase inhibitors (MAOIs), can interact with Flexeril and cause a life-threatening condition called serotonin syndrome 
• CNS depressants, such as sleep aids, anxiety medicines, opioid pain medicines, or phenobarbital
• Verapamil 

This is not a full list of drug interactions, and others may occur. Some interacting drug combinations should be avoided, and some can be managed with dosage adjustments and close monitoring. Talk to your healthcare provider for more information about drug interactions and how they affect you. 

Robaxin and Flexeril warnings

Muscle relaxants like Robaxin or Flexeril can cause increased dizziness or drowsiness and impair cognitive performance. Do not drive or operate machinery until you know how the medicine affects you. Avoid drinking alcohol while taking a muscle relaxant, as it can increase or worsen side effects.

Methocarbamol and cyclobenzaprine are not recommended in older adults. Both medications are on the BEERS list, a recognized list of medications prepared by the American Geriatrics Society. Muscle relaxants with CNS depressant effects can increase the risk of dizziness, falls, and serious injury in older adults. 

Muscle relaxants are generally not recommended in pregnant women. These drugs should be stored out of the reach of children. 

Muscle relaxants are sometimes abused and can cause physical dependence. Abrupt discontinuation of these drugs after long-term use can cause withdrawal symptoms. These medications should only be used under the supervision of a doctor or healthcare provider. 

Frequently asked questions about Robaxin vs. Flexeril

What is Robaxin?

Robaxin is a muscle relaxant that is FDA-approved to treat pain and discomfort from musculoskeletal conditions like sprains, back pain, and neck pain. It is available as a generic drug called methocarbamol. 

What is Flexeril?

Flexeril is a brand name for cyclobenzaprine, a commonly prescribed muscle relaxant for muscle pain and other musculoskeletal conditions. Cyclobenzaprine is available in immediate-release and extended-release forms. Flexeril is no longer available as a brand-name drug in the United States.

Are Robaxin and Flexeril the same?

Robaxin and Flexeril are both muscle relaxants. However, they are not the same drug. Robaxin contains methocarbamol and is usually dosed multiple times per day. Flexeril contains cyclobenzaprine and is available in an extended-release form that can be taken once per day (as well as an immediate-release form that can be taken up to three times daily). 

Is Robaxin or Flexeril better?

Robaxin and Flexeril are comparable in effectiveness. Some people may prefer extended-release cyclobenzaprine for its once-daily dosing. Cyclobenzaprine may be more sedating, but this may be beneficial for people who have trouble sleeping due to muscle spasms. Discuss these treatment options with a doctor to find the best medication for you. 

Can I use Robaxin or Flexeril while pregnant?

There are no adequate studies to show that Robaxin or Flexeril are safe or harmful during pregnancy. These medications should only be taken if their benefits outweigh the risks. Muscle relaxants should only be taken with medical guidance from a doctor. 

Can I use Robaxin or Flexeril with alcohol?

Do not consume alcohol while taking Robaxin or Flexeril. Alcohol can compound muscle-relaxant side effects such as drowsiness, dizziness, or loss of coordination. 

Which muscle relaxer is the strongest?

According to systematic reviews, almost all muscle relaxers are comparable in effectiveness. Cyclobenzaprine and tizanidine may be more sedating. However, cyclobenzaprine is one of the most studied muscle relaxers with strong evidence for its effectiveness.