Advertisement

Generic Name:

cyclobenzaprine, Oral tablet

All Brands

  • Fexmid
  • Flexeril
SECTION 1 of 5

Highlights for cyclobenzaprine

Oral tablet
1

Cyclobenzaprine is used to relieve muscle spasms. It’s used along with rest and physical therapy. It should only be used for 2–3 weeks at a time.

2

This drug comes in the form of a tablet or extended-release capsule (a drug that’s released more slowly into your body over time) you take by mouth.

3

Cyclobenzaprine is available as the brand-name drugs called Amrix and Fexmid. It’s also available as a generic drug.

4

The more common side effects of this drug include dizziness, drowsiness, dry mouth, and upset stomach.

5

In some cases, cyclobenzaprine can cause serious side effects. These include serotonin syndrome and heart problems.

IMPORTANT INFORMATION

Serotonin syndrome

This drug can cause a life-threatening condition called serotonin syndrome. This happens when medications cause too much serotonin to build up in your body. Call your doctor right away if you have any symptoms of this condition. These include agitation (a feeling of aggravation or restlessness), hallucinations (seeing or hearing something that isn’t there), seizures, or nausea. Your risk may be higher if you take cyclobenzaprine with other drugs that increase the risk of serotonin syndrome, such as antidepressants.

Effects on the heart

This drug may cause heart arrhythmias (heart rate or rhythm problems). Your risk may be higher if you take a drug to treat depression or if you already have heart problems. If these issues aren’t treated, they can lead to a heart attack or stroke.

Central nervous system effects

This drug can cause drowsiness, dizziness, hallucinations (seeing or hearing things that aren’t there), and delusions (believing things that aren’t true). You shouldn’t drive or use machinery while you’re on this medication until you know how it affects you. Your risk may be higher if you’re 65 years or older.

What is cyclobenzaprine?

Cyclobenzaprine is a prescription drug. It’s available as an oral tablet and oral extended-release capsule (a drug that’s released more slowly into your body over time).

Cyclobenzaprine is available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version.

Cyclobenzaprine may be used as part of a combination therapy. This means you may need to take it with other medications.

Why it's used

Cyclobenzaprine is used to help relax muscles. It helps relieve pain, stiffness, or discomfort caused by strains or injuries to your muscles. It’s used along with rest and physical therapy. It should only be used for 2–3 weeks at a time.

How it works

Cyclobenzaprine belongs to a class of drugs called muscle relaxants. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

More Details

How it works

Cyclobenzaprine belongs to a class of drugs called muscle relaxants. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

It isn’t known exactly how this drug works to relax your muscles. It may decrease the signals from your brain that tell your muscles to spasm.

Advertisement
SECTION 2 of 5

cyclobenzaprine Side Effects

Oral tablet

More Common Side Effects

The more common side effects of cyclobenzaprine can include:

  • dry mouth

  • dizziness

  • fatigue

  • constipation

  • drowsiness

  • nausea

  • heartburn

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Heart problems. Symptoms can include:

    • fainting
    • heart palpitations (fast or irregular heartbeat)
    • confusion
    • trouble speaking or understanding
    • loss of control or numbness in your face, arms, or legs
    • trouble seeing in one or both eyes
  • Serotonin syndrome. Symptoms can include:

    • agitation (a feeling of aggravation or restlessness)
    • hallucinations (hearing or seeing something that isn’t there)
    • seizures
    • nausea
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

When you first start taking this drug, you may have dry mouth, dizziness, fatigue, and nausea. This may also be more likely to happen when your doctor increases your dose.

Cyclobenzaprine may cause drowsiness and dizziness. This is more likely to happen in the few hours after you take it.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 5

cyclobenzaprine May Interact with Other Medications

Oral tablet

Cyclobenzaprine can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Alcohol interaction

The use of drinks that contain alcohol can increase your risk of dizziness, drowsiness, and decreased alertness from cyclobenzaprine. If you drink alcohol, talk to your doctor.

Medications that might interact with this drug

Drugs you should not take with cyclobenzaprine

Do not take these drugs with cyclobenzaprine. Doing so can cause dangerous effects in the body. Examples of these drugs include:

  • Monoamine oxidase inhibitors (MAOIs), such as selegiline, rasagiline, and tranylcypromine. Taking this drug with an MAOI or within 14 days of stopping an MAOI could increase your risk of serious side effects. These include seizures.

Interactions that increase your risk of side effects

Side effects from cyclobenzaprine: Taking cyclobenzaprine with certain medications raises your risk of side effects from cyclobenzaprine. This is because the amount of cyclobenzaprine in your body is increased. Examples of these drugs include:

  • Benzodiazepines, such as triazolam, alprazolam, and midazolam. You may have more sedation and drowsiness.
  • Barbiturates, such as phenobarbital. You may have more sedation and drowsiness.
  • Certain drugs used to treat depression, such as fluoxetine, venlafaxine, amitriptyline, or bupropion. You may be at a greater risk for serotonin syndrome.
  • Verapamil. You may be at a greater risk for serotonin syndrome.
  • Anticholinergic drugs, such as tolterodine or oxybutynin. You may be at a greater risk for certain side effects. These include dry mouth or not being able to urinate.

Interactions that can make your drugs less effective
  • When other drugs are less effective: When certain drugs are used with cyclobenzaprine, they may not work as well. Examples of these drugs include:
    • Guanethidine. Cyclobenzaprine can block the blood pressure-lowering effect of this drug. This means your blood pressure may increase.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Cyclobenzaprine warnings
trouble urinating
People with trouble urinating

This drug can make your symptoms worse.

glaucoma
People with glaucoma

This drug can make your symptoms worse.

liver problems
People with liver problems

If you have liver problems or a history of liver disease, you may not be able to clear this drug from your body well. This may cause it to build up in your body. This raises your risk of side effects. You shouldn’t use the extended-release form of this drug if you have liver problems.

pregnant women
Pregnant women

Cyclobenzaprine is a category B pregnancy drug. That means two things:

  1. Research in animals hasn’t shown a risk to the fetus when the mother takes the drug.
  2. There aren’t enough studies done in humans to show if the drug poses a risk to the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. Animal studies don’t always predict the way humans would respond. Therefore, this drug should only be used in pregnancy if clearly needed.

breast-feeding
Women who are breast-feeding

Cyclobenzaprine may pass into breast milk and may cause side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your child. You may need to decide whether to stop breast-feeding or stop taking this medication.

for seniors
For seniors

The kidneys and liver of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

If you’re older than 65, you shouldn’t use the extended-release form of this drug.

for children
For children

The oral tablet shouldn’t be used in people younger than 15 years.

The extended-release form of this drug shouldn’t be used in people younger than 18 years.

allergies
Allergies

Cyclobenzaprine can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your throat or tongue

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

SECTION 4 of 5

How to Take cyclobenzaprine (Dosage)

Oral tablet

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Relief of muscle spasms

Generic: Cyclobenzaprine

Form: Oral tablet
Strengths: 5 mg, 10 mg

Brand: Fexmid

Form: Oral tablet
Strengths: 7.5 mg

Brand: Amrix

Form: Oral extended-release capsule
Strengths: 15 mg, 30 mg
Adult dosage (ages 18–64 years)
  • Oral tablet: 5–10 mg taken 3 times per day
  • Oral extended-release capsule: 15 mg taken once per day. If your muscle spasms don’t get better, your doctor may increase your dose to 30 mg per day.

Oral tablet:

Child dosage (ages 15–17 years)

5–10 mg taken 3 times per day

Oral extended-release capsule:

Child dosage (ages 0–14 years)

This drug shouldn’t be used in people younger than 15 years.

Child dosage (ages 0–17 years)

This drug shouldn’t be used in people younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

  • Oral tablet: Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
  • Oral extended-release capsule: You shouldn’t use this form of the drug.
Special considerations

People with liver problems:

  • Oral tablet: If your liver problems are mild, your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body. If your liver problems are moderate or severe, you shouldn’t use this drug.
  • Oral extended-release capsule: If you have liver problems, you shouldn’t use this form of the drug.

Warnings

You shouldn’t use this drug for more than 2–3 weeks.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Cyclobenzaprine comes with serious risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

Your symptoms may get worse. You may have more muscle spasms or pain.

If you miss doses or don’t take the drug on schedule

Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much

You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • fainting
  • heart palpitations (fast or irregular heartbeat)
  • confusion
  • trouble speaking or understanding
  • loss of control or numbness in your face, arms, or legs
  • trouble seeing in one or both eyes
  • agitation (a feeling of aggravation or restlessness)
  • hallucinations (hearing or seeing something that isn’t there)
  • seizures
  • nausea

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room right away. 

What to do if you miss a dose

Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working

You should have less muscle pain and stiffness.

Cyclobenzaprine is used for short-term treatment.

You shouldn’t use this drug for more than 2–3 weeks.

Important considerations for taking cyclobenzaprine
take with or without food
You can take cyclobenzaprine with or without food
timing
Take this drug at about the same time each day
cannot crush or cut
You can cut or crush the tablet. Don’t cut, crush, chew, or open up the capsules.
storage
Store this drug carefully
See Details
refillable
A prescription for this medication is refillable
See Details
travel
Travel
See Details
clinical monitoring
Clinical monitoring
See Details
not usually stocked
Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead.
prior authorization
Insurance
See Details

Store this drug carefully

  • Store cyclobenzaprine at room temperature. Keep it at 77°F (25°C). Keep it away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

A prescription for this medication is refillable

You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
  • Don’t worry about airport x-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

If you have liver problems, you doctor may do a blood test to monitor how well your liver is working while you take this drug.

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

SECTION 5 of 5

How Much Does cyclobenzaprine Cost?

Oral tablet

We've partnered with GoodRx so you can compare prices, find discounts and save up to 80% on your next prescription. Check out the low coupon prices below — no insurance required.

Compare prices and save up to 80% on your next refill!

Lowest price for cyclobenzaprine

Kroger Pharmacy $9.88
Walmart $10.00
Sams Club $10.02
These prices represent the lowest priced national pharmacies for cyclobenzaprine on GoodRx. They may be lower than your insurance.

Enter your zip code to find the best deal near you.

These prices represent the lowest priced national pharmacies for cyclobenzaprine on GoodRx. They may be lower than your insurance.

Show Sources

Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on December 9, 2015

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
Advertisement
Advertisement
Advertisement