Brand Name: Flexeril, Amrix and Fexmid
Generic Name: Cyclobenzaprine
Drug Class: Skeletal Muscle Relaxants
| Product Name | Price | Shipping | Total | Order |
| Cyclobenzaprine (Generic Flexeril 10mg) 180 pills | $159 | free | $159 | Order |
| Cyclobenzaprine (Generic Flexeril 10mg) 120 pills | $139 | free | $139 | Order |
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| Butalbital/APAP/Caffeine – 50/325/40 mg- 120 Tabs | $219 | free | $219 | Order |
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| Gabapentin 400 mg 180 Tabs | $179 | free | $179 | Order |
| Gabapentin 600 mg 180 Tabs | $195 | free | $195 | Order |
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Cyclobenzaprine hydrochloride is a white, crystalline tricyclic amine salt with the empirical formula C20H21N•HCl and a molecular weight of 311.9. It has a melting point of 217°C, and a pKa of 8.47 at 25°C. It is freely soluble in water and alcohol, sparingly soluble in isopropanol, and insoluble in hydrocarbon solvents. If aqueous solutions are made alkaline, the free base separates.
Cyclobenzaprine HCl is designated chemically as 3-(5H-dibenzo[a,d] cyclohepten-5-ylidene)-N, Ndimethyl- 1-propanamine hydrochloride, and has the following structural formula:
FLEXERIL 5 mg (Cyclobenzaprine HCl) is supplied as a 5 mg tablet for oral administration. FLEXERIL 10 mg (Cyclobenzaprine HCl) is supplied as a 10 mg tablet for oral administration.
FLEXERIL tablets contain the following inactive ingredients: hydroxypropyl cellulose, hydroxypropyl methylcellulose, iron oxide, lactose, magnesium stearate, starch, and titanium dioxide. FLEXERIL 5 mg tablets also contain Yellow D&C #10 Aluminum Lake HT, and Yellow FD&C #6 Aluminum Lake.
What Health Conditions Does Flexeril Treat ( Off-label Uses of Flexeril )?
Cyclobenzaprine is used, in conjunction with physical therapy, to treat muscle spasms that occur because of acute musculoskeletal conditions. After sustaining an injury, muscle spasms occur to stabilize the affected body part, which may increase pain to prevent further damage.
Cyclobenzaprine is used to treat such muscle spasms associated with acute, painful musculoskeletal conditions. It decreases pain in the first two weeks, peaking in the first few days, but has no proven benefit after two weeks. Since no benefit is proven beyond that, therapy should not be continued long-term. It is the best-studied muscle relaxer. It is not useful for spasticity due to neurologic conditions such as cerebral palsy.
It may also be used along with other treatments for tetanus.
Flexeril (generic name: cyclobenzaprine) is a muscle relaxant commonly prescribed for short-term relief of muscle spasms associated with acute musculoskeletal conditions. It’s FDA-approved for this use, typically alongside rest and physical therapy.
Flexeril can treat Muscle Spasm, Sciatica, Fibromyalgia, migraine, Chronic Myofascial Pain, and Joint Disorder. Common off-label uses include:
1. Fibromyalgia
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- Why used: For its potential to reduce muscle pain and improve sleep.
- Evidence: Some studies suggest low-dose cyclobenzaprine, especially taken at night, may improve sleep quality and reduce fibromyalgia-related pain.
- Typical dosage: Lower than the dose used for muscle spasms (e.g., 5–10 mg at bedtime).
2. Insomnia
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- Why used: Due to its sedating effects similar to tricyclic antidepressants (TCAs).
- Evidence: Used off-label when insomnia is related to muscle pain or when TCAs are not suitable.
- Caution: Not typically first-line for insomnia due to risk of next-day drowsiness and anticholinergic side effects.
3. Temporomandibular Joint Disorders (TMJ)
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- Why used: To relax jaw muscles and reduce associated pain.
- Evidence: Some case reports and clinical experience support its use, particularly for patients with muscle-based TMJ dysfunction.
4. Tension Headaches
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- Why used: Muscle relaxation can relieve tension-type headaches originating from neck/shoulder muscle strain.
- Evidence: Limited, but may be tried when headaches are associated with muscle tightness.
5. Neuropathic Pain or Chronic Pain Syndromes
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- Why used: As part of multi-drug regimens for pain management, especially when muscle tension is a component.
- Evidence: Sparse, and typically used only after other options fail.
6. Spasticity (off-label, not first-line)
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- Why used: Occasionally used when other muscle relaxants like baclofen or tizanidine are not tolerated.
- Note: Cyclobenzaprine is not ideal for conditions like multiple sclerosis or cerebral palsy where spasticity is due to CNS damage.
How Does Flexeril Work ?
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CNS Depression (Central Nervous System)
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Flexeril reduces tonic somatic motor activity by influencing both alpha and gamma motor neurons in the brainstem.
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This leads to a reduction in muscle spasms without interfering with overall muscle function.
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Structurally Similar to Tricyclic Antidepressants (TCAs)
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It shares a similar chemical structure with drugs like amitriptyline.
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Because of this, it also:
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Blocks norepinephrine reuptake to a small extent.
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Has anticholinergic properties (causing dry mouth, drowsiness, etc.).
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May indirectly affect serotonin pathways (though not fully understood).
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No Direct Action on the Neuromuscular Junction
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It doesn’t affect muscles themselves or nerves that directly innervate muscles, which distinguishes it from drugs like dantrolene.
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What is Flexeril and What Are the Side Effects of Flexeril ?
Flexeril (Cyclobenzaprine) works primarily as a centrally-acting muscle relaxant, which means it doesn’t act directly on muscles or nerves at the site of injury, but instead affects the brain and spinal cord.
What is Flexeril
Warnings
You should not use Flexeril if you have a thyroid disorder, heart block, congestive heart failure, a heart rhythm disorder, or you have recently had a heart attack. Do not use cyclobenzaprine if you have taken an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, or tranylcypromine.Before taking this medicine
You should not use Flexeril if you are allergic to cyclobenzaprine, or if you have:- a thyroid disorder;
- heart block, heart rhythm disorder, congestive heart failure; or
- if you have recently had a heart attack.
- liver disease;
- glaucoma;
- enlarged prostate; or
- problems with urination.
WHAT IS CYCLOBENZAPRINE AND HOW DOES IT WORK?
- 5 mg
- 7.5 mg
- 10 mg
- 15 mg
- 30 mg
- Adult: 5 mg orally every 8 hours, may increase dose to 7.5-10 mg orally every 8 hours as needed
- Under 15 years of age: Safety and efficacy not established
- Over 15 years of age: 5 mg orally every 8 hours, may increase dose to 7.5 mg orally every 8 hours as needed
- Geriatric: Immediate-release tablet: 5 mg/day orally initially; dose slowly upward and consider less frequent dosing
- Adult 15 mg orally once per day; some patients may require up to 30 mg orally once per day
- Under 18 years of age: Safety and efficacy not established
- Geriatric: Extended-release capsule not recommended in elderly, because of increased plasma levels (40%) and prolonged half-life (56%) compared with young adults
- Immediate-release tablet: 5 mg/day orally initially; dose slowly and consider less frequent dosing
- Extended-release capsule: Not recommended in mild-to-severe hepatic impairment
- Not studied
For the Consumer
Applies to cyclobenzaprine: oral capsule extended release, oral suspension, oral tabletSide effects requiring immediate medical attention
Along with its needed effects, cyclobenzaprine (the active ingredient contained in Flexeril) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Check with your doctor immediately if any of the following side effects occur while taking cyclobenzaprine: Rare- Clumsiness or unsteadiness
- confusion
- fainting
- mental depression
- problems in urinating
- ringing or buzzing in the ears
- skin rash, hives, or itching occurring without other symptoms of an allergic reaction listed above
- unusual thoughts or dreams
- yellow eyes or skin
- Convulsions (seizures)
- drowsiness (severe)
- dry, hot, flushed skin
- fast or irregular heartbeat
- hallucinations (seeing, hearing, or feeling things that are not there)
- increase or decrease in body temperature
- troubled breathing
- unexplained muscle stiffness
- unusual nervousness or restlessness (severe)
- vomiting (occurring together with other symptoms of overdose)
Side effects not requiring immediate medical attention
Some side effects of cyclobenzaprine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. More common- Blurred vision
- dizziness, drowsiness, or lightheadedness
- dryness of the mouth
- Bloated feeling or gas, indigestion, nausea or vomiting, or stomach cramps or pain
- constipation
- diarrhea
- excitement or nervousness
- frequent urination
- general feeling of discomfort or illness
- headache
- muscle twitching
- numbness, tingling, pain, or weakness in hands or feet
- pounding heartbeat
- problems in speaking
- trembling
- trouble sleeping
- unpleasant taste or other taste changes
- unusual muscle weakness
- unusual tiredness
- isocarboxazid
- phenelzine
- tranylcypromine
- desipramine
- dimenhydrinate
- donepezil
- eucalyptus
- galantamine
- sage
- tacrine
- trazodone
WHAT ARE WARNINGS AND PRECAUTIONS FOR CYCLOBENZAPRINE?
Warnings
- This medication contains cyclobenzaprine. Do not take Flexeril, Amrix or Fexmid if you are allergic to cyclobenzaprine or any ingredients contained in this drug
- Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately
- Avoid use if hypersensitivity to cyclobenzaprine or if you have hyperthyroidism
- During the acute recovery phase of myocardial infarction and in patients with irregular heartbeat, heart block or conduction disturbances, or congestive heart failure
- Do not use simultaneously or within 14 days of discontinuing antidepressants
- Hyperpyretic crisis seizures and deaths have occurred in patients receiving cyclobenzaprine (or similar tricyclic antidepressants) simultaneously with antidepressants
- May cause drowsiness/dizziness; do not ingest alcohol or other central nervous system depressants as it may impair ability to operate heavy machinery
- May cause drowsiness/dizziness; do not ingest alcohol or other central nervous system depressants as it may impair ability to operate heavy machinery
- See "What Are Side Effects Associated with Using Cyclobenzaprine?"
- Cyclobenzaprine use is only recommended for short periods, 2-3 weeks
- See "What Are Side Effects Associated with Using Cyclobenzaprine?"
- Use only for short periods, 2-3 weeks
- Use caution in urinary retention, narrow-angle glaucoma or intensive outpatient program, or simultaneous use of other anticholinergic drugs
- May cause drowsiness/dizziness; do not ingest alcohol or other central nervous system depressants as it may impair ability to operate heavy machinery
- May take with food to avoid stomach upset
- Serotonin syndrome reported when co-administered with other drugs that increase serotonin (for example selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, tramadol, bupropion, meperidine, verapamil, or anti-depressants [see also Contraindications])
- Not effective for treatment of spasticity associated with cerebral/spinal cord disease or for pediatric cerebral palsy
- Elderly patients may be more prone to adverse effects and require dose/frequency reduction
- Use immediate release with caution in hepatic impairment; avoid extended-release form as it is not recommended with hepatic impairment
- Cyclobenzaprine use in pregnancy may be acceptable
- Either animal studies show no risk but human studies are not available or animal studies showed minor risks and human studies were done and showed no risk
- Consult with your physician prior to use
- Cyclobenzaprine excretion in breast milk is unknown
- Use with caution
- Consult with your physician prior to use
Cyclobenzaprine is used with rest, physical therapy, and other measures to relax muscles and relieve pain and discomfort caused by strains, sprains, and other muscle injuries. Cyclobenzaprine is in a class of medications called skeletal muscle relaxants. It works by acting in the brain and nervous system to allow the muscles to relax.
How Should Cyclobenzaprine be Used?
Cyclobenzaprine comes as a tablet and an extended-release capsule to take by mouth. The tablet is usually taken with or without food three times a day. The extended-release capsule is usually taken with or without food once a day. Do not take this drug for more than 3 weeks without talking to your doctor. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take cyclobenzaprine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow the extended-release capsules whole; do not chew or crush them.
If you are not able to swallow the extended-release capsule whole, mix the contents of the capsule with applesauce. Eat the mixture right away and swallow without chewing. After you eat the mixture, take a drink, and swish and swallow to make sure that you have received all the medication.
What Special Precautions Should I Follow?
Before taking cyclobenzaprine,
- tell your doctor and pharmacist if you are allergic to cyclobenzaprine, any other medications, or any of the ingredients in cyclobenzaprine tablets or capsules. Ask your pharmacist for a list of the ingredients.
- tell your doctor if you are taking the following medications or have stopped taking them within the past two weeks: monoamine oxidase (MAO) inhibitors, including isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate). Your doctor will probably tell you not to take cyclobenzaprine if you are taking one of these medications.
- tell your doctor and pharmacist what other prescription and nonprescription drugs, vitamins, nutritional supplements and herbal products you are taking or plan to take. Be sure to mention any of the following: medications for allergies, coughs, or colds; barbiturates such as butabarbital (Butisol), phenobarbital, and secobarbital (Seconal); bupropion (Aplenzin, Forfivo XL, Wellbutrin, Zyban); meperidine (Demerol); sedatives; sleeping pills; selective serotonin reuptake inhibitors (SSRIs) such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem, Selfemra, in Symbyax), fluvoxamine (Luvox), paroxetine (Brisdelle, Paxil, Pexeva), and sertraline (Zoloft); selective serotonin and norepinephrine reuptake inhibitors (SNRIs) such as desvenlafaxine (Khedezla, Pristiq), duloxetine (Cymbalta), levomilnacipran (Fetzima), milnacipran (Savella) and venlafaxine (Effexor); tranquilizers; tricyclic antidepressants (TCAs) such as amitriptyline, amoxapine, clomipramine (Anafranil), desipramine (Norpramin), doxepin (Silenor), imipramine (Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil); tramadol (Conzip, Ultram, in Ultracet); verapamil (Calan, Covera HS, Verelan, in Tarka); or any other medication for depression, mood, anxiety, or thought disorder. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with cyclobenzaprine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. ;
- tell your doctor if you are recovering from a recent heart attack, or if you have an overactive thyroid gland. heart failure (condition in which the heart is unable to pump enough blood to the other parts of the body), or an irregular heartbeat, heart block, or other problems with the electrical impulses of your heart. Your doctor will probably tell you not to take cyclobenzaprine.
- tell your doctor if you have increased pressure in the eye or glaucoma, difficulty urinating, or liver disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking cyclobenzaprine, call your doctor immediately.
- talk to your doctor about the risks and benefits of taking cyclobenzaprine if you are 65 years of age or older. Older adults should not usually take cyclobenzaprine because it is not as safe or effective as other medications that can be used to treat the same condition.
- you should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how cyclobenzaprine affects you.
- ask your doctor about the safe use of alcoholic beverages while you are taking cyclobenzaprine. Cyclobenzaprine can make the effects of alcohol worse.
What Should I do if I Forget a Dose?
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for the missed one.
What Should I Know About Storage and Disposal of Cyclobenzaprine?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Store the extended-release capsule away from light.
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org
In Case of Emergency/Overdose
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.
Symptoms of overdose may include the following:
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- drowsiness
- fast or irregular heartbeat
- feeling agitated
- confusion
- trouble speaking or moving
- dizziness
- nausea
- vomiting
- hallucination (seeing things or hearing voices that do not exist)
- tremor
- loss of consciousness
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What Other Information Should I Know?
Keep all appointments with your doctor.
Flexeril Comparison to Other Medications
Cyclobenzaprine has been found not to be inferior to tizanidine, orphenadrine, and carisoprodol in the treatment of acute lower back pain, although none have been proven to be effective for long-term use (beyond two weeks of treatment). No differences in pain or spasm scores were noted among these agents, nor when compared to benzodiazepines.
However, nonbenzodiazepine (including cyclobenzaprine) treatment was found to have a lower risk of medication abuse and continuation of use against medical advice. Side effects such as sedation and ataxia are also less pronounced with nonbenzodiazepine antispasmodics.
In a study on the treatment of musculoskeletal pain treatment with cyclobenzaprine alone or in combination with ibuprofen, no significant differences in pain scores were noted among the three treatment groups. Peak benefit was found to occur on day seven of the treatment for all groups.[19]
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
Brand names
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- Amrix®
- Flexeril®
Interactions
Cyclobenzaprine has major contraindications with monoamine oxidase inhibitors (MAOIs). At least one study also found increased risk of serotonin syndrome when cyclobenzaprine was taken with the serotonergic drugs duloxetine or phenelzine.
These substances may interact with cyclobenzaprine:
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- Central nervous system depressants (e.g. alcohol, opioids, benzodiazepines, nonbenzodiazepines, phenothiazines, carbamates, barbiturates, major tranquilizers)
- Monoamine oxidase inhibitors taken within two weeks of cyclobenzaprine may result in serious, life-threatening side effects.
Cyclobenzaprine may affect the medications used in surgical sedation and some surgeons request that patients temporarily discontinue its use prior to surgery.