What is cyclobenzaprine and What is Cyclobenzaprine side effects ?

What is cyclobenzaprine?

Cyclobenzaprine oral tablet is a prescription drug that’s available as the brand-name drug Fexmid.

It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in all strengths or forms as the brand-name drug.

Cyclobenzaprine also comes as an oral extended-release capsule.

Brand Name: Flexeril, Amrix and Fexmid

Generic Name: Cyclobenzaprine

Drug Class: Skeletal Muscle Relaxants

 

WHAT IS CYCLOBENZAPRINE AND HOW DOES IT WORK?

Cyclobenzaprine is a prescription drug used short-term to treat muscle spasms. It is usually used along with rest and physical therapy. It works by helping to relax the muscles.

Cyclobenzaprine is available under the following different brand names: Flexeril, Amrix and Fexmid.

Dosages of Cyclobenzaprine:

Tablet (adult and pediatric)

      • 5 mg
      • 7.5 mg
      • 10 mg

Capsule, extended-release (adult only)

      • 15 mg
      • 30 mg

Dosage Considerations – Should be Given as Follows:

Take this medication by mouth with or without food as directed by your doctor, usually once daily. Swallow the capsules whole. Do not crush or chew the capsules. Doing so can release all of the drug at once, increasing the risk of side effects.

This medication is not recommended for use in older adults because they may be at greater risk for side effects while using this drug.

This medication should only be used short-term (for 3 weeks or less) unless directed by your doctor. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.

Muscle Spasm

Immediate-release tablet

  • 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

Extended-release capsule

  • 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
  • Dosing Modifications
  • Hepatic impairment
  • 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

Why it’s used

Cyclobenzaprine oral tablet 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 two to three weeks at a time.

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

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.

The primary adverse effects of cyclobenzaprine

The primary adverse effects of cyclobenzaprine include dizziness, xerostomia, drowsiness, fatigue, headache, nervousness, and confusion. Like other cyclical antidepressants, cyclobenzaprine antagonizes the muscarinic receptors, which may produce undesired side effects such as xerostomia, ileus, tachycardia, mydriasis, confusion, and hallucinations. Additionally, like other cyclical antidepressants, cyclobenzaprine antagonizes the alpha1 adrenergic receptor, causing a vasodilatory effect, and may contribute further to reflex tachycardia. The most common adverse effects seen with cyclobenzaprine are somnolence, dry mucous membranes, dizziness, and confusion

Cyclobenzaprine side effects

Cyclobenzaprine oral tablet may cause drowsiness and dizziness. This is more likely to happen in the few hours after you take it. It can also have other side effects.

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 911 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

You can not take Prescription for a long time, you need find a way to treat your pain without prescription. Exercising is the best way to relieve your pain. because exercising can enhance your immune system and increase your muscle strength and make your nerve strong.

You can also take some natural nutritions to increase your immune system too.

Some anti-aging products can also increase your immune ability. You can try USANA Products to make you strong. I take USANA Essentials every day and I find my health get better and better.

Flexeril Effects and Abuse

Taking Flexeril can improve sleep, motor skills, and energy levels in consumers that are experiencing severe muscle pain. In addition to these benefits, the medication can produce a variety of negative and potentially harmful effects as well. These side effects can range from mild to severe and include any of the following:

      • Drowsiness
      • Dry mouth
      • Fatigue
      • Headaches
      • Dizziness
      • Nausea
      • Constipation
      • Blurred vision
      • Confusion
      • Acid reflux
      • Abdominal pain
      • Fever
      • Nervousness
      • Urination problems

Another potential side effect of Flexeril is overdose if an individual takes too much of the drug. Although Flexeril doesn’t produce a euphoric high like many other drugs, people still misuse it due to its relaxing effects, and many will increase dosages to amplify those effects.

A Flexeril overdose can cause severe health problems such as cardiac arrest, dangerously low blood pressure, and seizures. In extreme cases, central nervous system depression, seizures, heart attack and even death can occur. Signs of overdose include chest pain, hallucinations, vomiting, rapid heartbeat, slurred speech, difficulty breathing, and extreme drowsiness. The risk of overdose is significantly increased when Flexeril is combined with other drugs, particularly central nervous system depressants such as alcohol or benzodiazepines.

This combination can cause extreme drowsiness and respiratory depression, but many people that abuse Flexeril will mix them anyway simply to increase the intoxication experienced.

Signs of a Flexeril Addiction

Professionals generally consider Flexeril to be non-addictive; however, there is evidence that Flexeril addiction is possible. Flexeril depresses the central nervous system, and some people find these effects to be desirable, which can lead to misuse. An individual might abuse Flexeril in order to feel relaxed, mildly euphoric, or sedated.

In high doses, Flexeril produces a variety of anticholinergic effects, altering the activity of brain neurotransmitters. Chronic use of the drug can then cause physical dependence; a person that was simply taking a higher dose of Flexeril due to pain can become accustomed to the presence of the drug in the system and develop an addiction as a result.

Additionally, Flexeril users may experience mild withdrawal symptoms if the drug is used chronically in high doses.

Signs that indicate someone may have a Flexeril addiction include:

    • Taking Flexeril after it’s no longer needed or longer then prescribed
    • Needing more and more of the drug to elicit the same effects
    • Spending the majority of the day thinking about Flexeril: how to get more, the effects it produces, and when to use it
    • Constantly using Flexeril and being unable to stop
    • Faking symptoms to get Flexeril prescriptions
    • Sudden changes in physical appearance, hygiene, and behavior

Another tall-tell sign of Flexeril addiction is abusing the medication in combination with another substance to produce a greater sense of euphoria. Alcohol is commonly abused alongside muscle relaxers like Flexeril because it heightens the side effects of both, causing the individual to experience a more intense sedation or high. People might also use Flexeril as a way to come down from stimulant drugs, such as cocaine or Adderall. When someone that is addicted to the drug attempts to stop taking it or reduce doses, he or she will start to experience withdrawal symptoms although they are typically not severe. Flexeril withdrawal symptoms can include headache, nausea, fatigue, and cravings for the drug.

Index Terms

  • Cyclobenzaprine HCl
  • Cyclobenzaprine Hydrochloride
  • Flexeril

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule Extended Release 24 Hour, Oral, as hydrochloride:

Amrix: 15 mg [contains fd&c red #40, fd&c yellow #10 (quinoline yellow)]

Amrix: 30 mg [contains brilliant blue fcf (fd&c blue #1), fd&c blue #2 (indigotine), fd&c red #40, fd&c yellow #6 (sunset yellow)]

Generic: 15 mg, 30 mg

Tablet, Oral, as hydrochloride:

Fexmid: 7.5 mg

Generic: 5 mg, 7.5 mg, 10 mg

Brand Names: U.S.

  • Amrix
  • Fexmid

Pharmacologic Category

  • Skeletal Muscle Relaxant

Pharmacology

Centrally-acting skeletal muscle relaxant pharmacologically related to tricyclic antidepressants; reduces tonic somatic motor activity influencing both alpha and gamma motor neurons

Metabolism

Hepatic via CYP3A4, 1A2, and 2D6; may undergo enterohepatic recirculation

Excretion

Urine (primarily as glucuronide metabolites); feces (as unchanged drug; Hucker, 1978); Clearance: 0.7 L/minute

Onset of Action

Immediate release: Within 1 hour

Immediate release: ~4 hours (Winchell 2002); Extended release: 7 to 8 hours

Duration of Action

Immediate release: 12 to 24 hours

Half-Life Elimination

Normal hepatic function: Range: 8 to 37 hours; Immediate release: 18 hours; Extended release: 32 hours; Impaired hepatic function: 46.2 hours (range: 22.4 to 188 hours) (Winchell 2002)

Special Populations: Hepatic Function Impairment

In mild-to-moderate hepatic impairment, AUC and Cmax increased approximately twofold with immediate-release cyclobenzaprine.

Special Populations: Elderly

AUC increased ~2.4-fold in elderly males and ~1.2-fold in elderly females with immediate-release cyclobenzaprine. AUC increased 40% and the plasma half-life is prolonged (50 hours) in elderly subjects with extended-release cyclobenzaprine.

Use: Labeled Indications

Muscle spasm: As an adjunct to rest and physical therapy for short-term (2 to 3 weeks) relief of muscle spasm associated with acute, painful musculoskeletal conditions.

Off Label Uses

Fibromyalgia

Data from multiple double-blind, placebo-controlled trials [Bennett 1988][Quimby 1989] support the use of cyclobenzaprine in the treatment of fibromyalgia.

Based on the European League Against Rheumatism revised recommendations for the management of fibromyalgia, cyclobenzaprine is recommended as an alternative agent in the management of this condition [EULAR [Macfarlane 2017]].

Temporomandibular disorder, acute

Data from 2 randomized, double-blind, placebo-controlled trials of patients experiencing myofascial jaw pain upon awakening suggest that cyclobenzaprine at bedtime may have some benefit for the treatment of acute jaw pain due to temporomandibular disorder [Alencar 2014][Herman 2002]. Of note, 1 study demonstrated significant improvement in pain scores with treatment; however, no significant differences were seen compared to placebo [Alencar 2014].

Contraindications

Hypersensitivity to cyclobenzaprine or any component of the formulation; during or within 14 days of MAO inhibitors; hyperthyroidism; heart failure; arrhythmias; heart block or conduction disturbances; acute recovery phase of MI

Dosing: Adult

Note: Patients more sensitive to sedating and other CNS adverse effects (eg, those who are older, debilitated patients, those with organ impairment) may better tolerate a reduced dose, less frequent administration, and/or more gradual titration (Chou 2019).

Fibromyalgia (alternative agent) (off-label use):

Note: For mild to moderate symptoms, particularly with sleep disturbance (EULAR [Macfarlane 2017]; Goldenberg 2020; Tofferi 2004).

Oral: Immediate release: Initial: 5 to 10 mg once daily before bedtime; may gradually titrate as needed and tolerated up to 10 to 40 mg daily in 1 to 3 divided doses (Calandre 2015; EULAR [Macfarlane 2017]; Goldenberg 2020; Tofferi 2004). If excessive sedation occurs, may divide dose so larger portion is taken at bedtime (eg, 5 mg in morning and 10 or 15 mg at bedtime) (Goldenberg 2020; Tofferi 2004).

Muscle spasm and/or musculoskeletal pain (adjunctive therapy):

Note: For skeletal muscle spasm and/or pain (eg, low back pain, neck pain) with muscle spasm, usually in combination with a nonsteroidal anti-inflammatory drug (NSAID) and/or acetaminophen (ACP [Chou 2017]; Borenstein 2003; van Tulder 2003). In general, muscle relaxants should be used temporarily (eg, for a few days or intermittently for a few days when needed) (APS 2016).

Oral: Immediate release: Initial: 5 mg 3 times daily scheduled or as needed with one of the doses administered at bedtime (Chou 2019). May increase dose based on response and tolerability up to 10 mg 3 times daily as needed. Once-daily use at bedtime (with daytime NSAID and/or acetaminophen) may be better tolerated (Knight 2020).

Oral: Extended release: Usual: 15 mg once daily; some patients may require up to 30 mg once daily.

Temporomandibular disorder, acute (adjunctive therapy) (off-label use):

Note: Adjunct to an NSAID in select patients with pain on palpation of the lower jaw muscle (Alencar 2014; Herman 2002; Mehta 2019).

Oral: Immediate release: Usual: 10 mg once daily at bedtime for 10 to 14 days (Alencar 2014; Herman 2002; Mehta 2019).

Dosing: Geriatric

Avoid use (Beers Criteria [AGS 2019]).

Dosing: Pediatric

Muscle spasm, treatment: Adolescents ?15 years: Oral: Immediate release tablet: Initial: 5 mg 3 times daily; may increase up to 10 mg 3 times daily if needed. Do not use longer than 2 to 3 weeks.

Administration

Oral: Extended release: Swallow whole and administer at the same time each day. Alternatively, the contents of the capsule may be sprinkled onto a tablespoon of applesauce and consume immediately without chewing; rinse mouth to ensure all contents have been swallowed; discard any unused portion of capsule.

Storage

Capsules: Store at 25°C (77°F); excursions are permitted to 15°C to 30°C (59°F to 86°F).

Tablets: Store between 20°C and 25°C (68°F and 77°F).

Drug Interactions

Acetylcholinesterase Inhibitors: May diminish the therapeutic effect of Anticholinergic Agents. Anticholinergic Agents may diminish the therapeutic effect of Acetylcholinesterase Inhibitors. Monitor therapy

Aclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Monitor therapy

Alizapride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Amantadine: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Anticholinergic Agents: May enhance the adverse/toxic effect of other Anticholinergic Agents. Monitor therapy

Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination

Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Management: Use caution if coadministering blonanserin and CNS depressants; dose reduction of the other CNS depressant may be required. Strong CNS depressants should not be coadministered with blonanserin. Consider therapy modification

Botulinum Toxin-Containing Products: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Botulinum Toxin-Containing Products: Muscle Relaxants (Centrally Acting) may enhance the adverse/toxic effect of Botulinum Toxin-Containing Products. Specifically, the risk for increased muscle weakness may be enhanced. Monitor therapy

Brexanolone: CNS Depressants may enhance the CNS depressant effect of Brexanolone. Monitor therapy

Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Bromopride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Bromperidol: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine at lower doses in patients already receiving CNS depressants. Consider therapy modification

Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Chloral Betaine: May enhance the adverse/toxic effect of Anticholinergic Agents. Monitor therapy

Chlormethiazole: May enhance the CNS depressant effect of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Consider therapy modification

Chlorphenesin Carbamate: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Cimetropium: Anticholinergic Agents may enhance the anticholinergic effect of Cimetropium. Avoid combination

CloZAPine: Anticholinergic Agents may enhance the constipating effect of CloZAPine. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for signs and symptoms of gastrointestinal hypomotility and consider prophylactic laxative treatment. Consider therapy modification

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Monitor therapy

Dimethindene (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Monitor therapy

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (eg, opioids, barbiturates) with concomitant use. Exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Consider therapy modification

Eluxadoline: Anticholinergic Agents may enhance the constipating effect of Eluxadoline. Avoid combination

Esketamine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification

Gastrointestinal Agents (Prokinetic): Anticholinergic Agents may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Monitor therapy

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Monitor therapy

Glycopyrrolate (Oral Inhalation): Anticholinergic Agents may enhance the anticholinergic effect of Glycopyrrolate (Oral Inhalation). Avoid combination

Glycopyrronium (Topical): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Ipratropium (Oral Inhalation): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Itopride: Anticholinergic Agents may diminish the therapeutic effect of Itopride. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Lemborexant: May enhance the CNS depressant effect of CNS Depressants. Management: Dosage adjustments of lemborexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive CNS depressant effects. Close monitoring for CNS depressant effects is necessary. Consider therapy modification

Levosulpiride: Anticholinergic Agents may diminish the therapeutic effect of Levosulpiride. Avoid combination

Lisuride: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Lofexidine: May enhance the CNS depressant effect of CNS Depressants. Management: Drugs listed as exceptions to this monograph are discussed in further detail in separate drug interaction monographs. Monitor therapy

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce the usual dose of CNS depressants by 50% if starting methotrimeprazine until the dose of methotrimeprazine is stable. Monitor patient closely for evidence of CNS depression. Consider therapy modification

Metoclopramide: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy

Mianserin: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Minocycline (Systemic): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mirabegron: Anticholinergic Agents may enhance the adverse/toxic effect of Mirabegron. Monitor therapy

Monoamine Oxidase Inhibitors: Cyclobenzaprine may enhance the serotonergic effect of Monoamine Oxidase Inhibitors. This could result in serotonin syndrome. Avoid combination

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Nitroglycerin: Anticholinergic Agents may decrease the absorption of Nitroglycerin. Specifically, anticholinergic agents may decrease the dissolution of sublingual nitroglycerin tablets, possibly impairing or slowing nitroglycerin absorption. Monitor therapy

Ombitasvir, Paritaprevir, and Ritonavir: May decrease the serum concentration of Cyclobenzaprine. Monitor therapy

Ombitasvir, Paritaprevir, Ritonavir, and Dasabuvir: May decrease the serum concentration of Cyclobenzaprine. Monitor therapy

Opioid Agonists: CNS Depressants may enhance the CNS depressant effect of Opioid Agonists. Management: Avoid concomitant use of opioid agonists and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination

Oxatomide: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Oxomemazine: May enhance the CNS depressant effect of CNS Depressants. Avoid combination

OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: Avoid concomitant use of oxycodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Consider therapy modification

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification

Piribedil: CNS Depressants may enhance the CNS depressant effect of Piribedil. Monitor therapy

Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Avoid combination

Potassium Citrate: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Citrate. Avoid combination

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Avoid combination

Ramosetron: Anticholinergic Agents may enhance the constipating effect of Ramosetron. Monitor therapy

Revefenacin: Anticholinergic Agents may enhance the anticholinergic effect of Revefenacin. Avoid combination

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Management: Avoid concomitant use of anticholinergic agents and secretin. Discontinue anticholinergic agents at least 5 half-lives prior to administration of secretin. Consider therapy modification

Serotonergic Agents (High Risk): Cyclobenzaprine may enhance the serotonergic effect of Serotonergic Agents (High Risk). This could result in serotonin syndrome. Management: Monitor for signs and symptoms of serotonin syndrome/serotonin toxicity (eg, hyperreflexia, clonus, hyperthermia, diaphoresis, tremor, autonomic instability, mental status changes) when these agents are combined. Exceptions: Isocarboxazid; Linezolid; Methylene Blue; Moclobemide; Phenelzine; Tranylcypromine. Monitor therapy

Sodium Oxybate: May enhance the CNS depressant effect of CNS Depressants. Management: Consider alternatives to combined use. When combined use is needed, consider minimizing doses of one or more drugs. Use of sodium oxybate with alcohol or sedative hypnotics is contraindicated. Consider therapy modification

Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Tetrahydrocannabinol and Cannabidiol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Thiazide and Thiazide-Like Diuretics: Anticholinergic Agents may increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Tiotropium: Anticholinergic Agents may enhance the anticholinergic effect of Tiotropium. Avoid combination

Tolperisone: May enhance the adverse/toxic effect of Muscle Relaxants (Centrally Acting). Management: Monitor for increased sedation or CNS effects if tolperisone is combined with other centrally acting muscle relaxants. Consider decreasing the tolperisone dose if these agents are combined. Consider therapy modification

Topiramate: Anticholinergic Agents may enhance the adverse/toxic effect of Topiramate. Monitor therapy

Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Umeclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification

Test Interactions

May cause false-positive serum TCA screen (Wong, 1995)

Adverse Reactions

>10%:

Central nervous system: Drowsiness (1% to 39%), dizziness (1% to 11%)

Gastrointestinal: Xerostomia (6% to 32%)

1% to 10%:

Central nervous system: Fatigue (1% to 6%), headache (1% to 5%), confusion (1% to 3%), decreased mental acuity (1% to 3%), irritability (1% to 3%), nervousness (1% to 3%)

Gastrointestinal: Dyspepsia (?4%), abdominal pain (1% to 3%), acid regurgitation (1% to 3%), constipation (1% to 3%), diarrhea (1% to 3%), nausea (1% to 3%), unpleasant taste (1% to 3%)

Neuromuscular & skeletal: Weakness (1% to 3%)

Ophthalmic: Blurred vision (1% to 3%)

Respiratory: Pharyngitis (1% to 3%), upper respiratory tract infection (1% to 3%)

<1%, postmarketing, and/or case reports: Abnormal dreams, abnormal hepatic function tests, abnormality in thinking, ageusia, agitation, anaphylaxis, angioedema, anorexia, anxiety, ataxia, cardiac arrhythmia, cholestasis, convulsions, depression, diaphoresis, diplopia, disorientation, dysarthria, excitement (paradoxical, children), facial edema, flatulence, gastritis, gastrointestinal pain, hallucination, hepatitis (rare), hypertonia, hypotension, increased thirst, insomnia, jaundice, malaise, muscle twitching, palpitations, paresthesia, pruritus, psychosis, seizure, serotonin syndrome, skin rash, syncope, tachycardia, tinnitus, tongue edema, tremor, urinary frequency, urinary retention, urticaria, vasodilation, vertigo, vomiting

Warnings/Precautions

Concerns related to adverse effects:

• Anticholinergic effects: Use with caution in patients with angle-closure glaucoma, increased intraocular pressure, or urinary frequency/hesitancy.

• CNS depression: May cause CNS depression, which may impair physical or mental abilities; ethanol and/or other CNS depressants may enhance these effects. Patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

• Serotonin syndrome: Potentially life-threatening serotonin syndrome has occurred with cyclobenzaprine when used in combination with other serotonergic agents (eg, SSRIs, SNRIs, TCAs, buspirone, meperidine, tramadol, MAO inhibitors), bupropion, and verapamil. Monitor patients closely especially during initiation/dose titration for signs/symptoms of serotonin syndrome such as mental status changes (eg, agitation, hallucinations); autonomic instability (eg, tachycardia, labile blood pressure, diaphoresis); neuromuscular changes (eg, tremor, rigidity, myoclonus); GI symptoms (eg, nausea, vomiting, diarrhea); and/or seizures. Discontinue cyclobenzaprine and any concomitant serotonergic agent immediately if signs/symptoms arise. Concomitant use or use within 14 days of discontinuing an MAO inhibitor is contraindicated.

• Toxicity: Cyclobenzaprine shares the toxic potentials of the tricyclic antidepressants, including prolongation of conduction time, arrhythmias, and tachycardia; the usual precautions of tricyclic antidepressant therapy should be observed.

Disease-related concerns:

• Hepatic impairment: Use with caution in patients with mild hepatic impairment; plasma concentrations increased twofold in presence of mild impairment. Not recommended in moderate-to-severe hepatic impairment. Extended release capsules not recommended in patients with hepatic impairment of any severity (mild, moderate, or severe).

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Elderly: Extended release capsules not recommended for use in elderly.

Other warnings/precautions:

• Appropriate use: Limit therapy to 2-3 weeks; efficacy has not been established for longer periods of use.

Pregnancy Considerations

Published information related to cyclobenzaprine use in pregnancy is limited (Flannery 1989; Moreira 2014).

Patient Education

What is this drug used for?

• It is used to relax muscles.

Frequently reported side effects of this drug

• Fatigue

• Dizziness

• Loss of strength and energy

• Dry mouth

• Constipation

• Nausea

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

• Fast heartbeat

• Abnormal heartbeat

• Serotonin syndrome like dizziness, severe headache, agitation, sensing things that seem real but are not, fast heartbeat, abnormal heartbeat, flushing, tremors, sweating a lot, change in balance, severe nausea, or severe diarrhea.

• Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

List of Common Muscle Relaxers

Muscle relaxers are used in addition to rest, physical therapy, and other measures to relieve discomfort. They are typically prescribed for short-term use to treat acute, painful musculoskeletal conditions. Muscle relaxers are occasionally prescribed for chronic pain (pain lasting longer than 3 months).

Product Name Price Shipping Total Order
Cyclobenzaprine (Generic Flexeril 10mg) 180 pills $159 free $159 Order
Zanaflex (Generic Tizanidine ) 4mg – 180 Tabs $156 free $156 Order
Methocarbamol (Gen. for Robaxin) 500mg – 180 Tabs $158 free $158 Order
Generic Fioricet – 180 Tabs $239 free $239 Order
Gabapentin 800 mg – 180 Tabs $189 free $189 Order

Muscle relaxers are not a class of drugs—meaning they do not all have the same chemical structure or work the same way in the brain. Rather, the term muscle relaxer is used to describe a group of drugs that act as central nervous system depressants and have sedative and musculoskeletal relaxant properties.

Muscle relaxers may be prescribed to treat back pain:

      • Early in the course of back pain, on a short-term basis, to relieve pain associated with muscle spasms
      • When back pain causes insomnia (for their sedative effect)

Muscle relaxers are also prescribed for other conditions such as fibromyalgia, multiple sclerosis, and seizure disorders.

There are several types of muscle relaxer medications commonly used to treat back pain.

muscle relaxant
muscle relaxant

Common Muscle Relaxants

Muscle relaxers are usually prescribed to treat back pain in conjunction with rest and physical therapy. Common muscle relaxants include:

      • Baclofen. Muscle tightness and muscle spasms, including those related to spine injuries, may be eased with baclofen. The medication may be helpful in treating multiple sclerosis and stabbing nerve pain. It is available as a tablet and can be taken by children as young as 12 years old. Some common side effects could include nausea and vomiting, confusion, drowsiness, headache, or muscle weakness. Baclofen is rated C in the FDA’s A through X pregnancy safety ranking for medications, with A being the safest. The C category means that the medication should only be used if the benefits outweigh the risks.
      • Benzodiazepines. In addition to treating anxiety, alcohol withdrawal, and seizure disorders, such as epilepsy, benzodiazepines can also treat muscle spasms and skeletal pain. Benzodiazepines, such as diazepam (Valium), lorazepam (Ativan), and temazepam (Restoril), are typically only intended for short-term use. This limitation is due to their habit-forming potential and because they alter sleep cycles, leading to sleep difficulties once the drug is stopped. Benzodiazepines are sold as tablets, liquid, injections, and rectal gels. People who have myasthenia gravis, severe liver disease, serious breathing troubles, or some forms of glaucoma, should avoid taking diazepam. All benzodiazepines are rated D by the FDA for safety during pregnancy and are not recommended for women who are pregnant.
      • Carisoprodol (Soma). Carisoprodol relaxes muscles and eases pain and stiffness caused by acute bone and muscle problems, often caused by an injury. It is taken by mouth in tablet form and is also available in combination with aspirin or aspirin and codeine. Carisoprodol can be habit-forming, particularly if used in conjunction with alcohol or other drugs that have a sedative effect, including opioids (such as codeine). Common side effects include drowsiness, dizziness, and headache. People with a history of blood disorders, kidney or liver disease, and seizures may need to avoid Carisoprodol. It is rated C in the FDA’s pregnancy safety ranking for medications.
      • Chlorzoxazone (Lorzone). Chlorzoxazone is used for the relief of discomfort from acute, painful, musculoskeletal conditions. Chlorzoxazone is available as a tablet. Common side effects include drowsiness, dizziness, and nausea. Chlorzoxazone is not recommended for people with liver disease. It has not been rated by the FDA for safety during pregnancy.
      • Cyclobenzaprine (Amrix, Fexmid, FlexePax Kit, FusePaq Tabradol). Cyclobenzaprine eases stiffness and pain from muscle cramps, also called muscle spasms. It is available as a tablet and extended-release capsule. Cyclobenzaprine itself is not intended for long-term use (more than 2 to 3 weeks). Common side effects include blurred vision, dizziness or drowsiness, and dry mouth. It is not advised for those with an overactive thyroid, heart problems, or liver disease. Cyclobenzaprine is rated B by the FDA for safety during pregnancy, making it the safest muscle relaxant to use while pregnant.
      • Dantrolene (Dantrium). Dantrolene helps control chronic spasticity related to spinal injuries. It is also used for conditions such as stroke, multiple sclerosis, and cerebral palsy. Dantrolene is taken as a capsule or intravenous powder for injection. Drowsiness and sensitivity to light are common side effects. It can cause severe liver problems, and should not be taken by people with active liver disease. The FDA has given dantrolene a C rating for safety in pregnancy.
      • Metaxalone (Skelaxin, Metaxall, and Metaxall CP, Lorvatus PharmaPak). Metaxalone targets pain and muscle spasms from sprains, strains, and muscle injuries. It is available as a tablet or injection. Common side effects include drowsiness, dizziness, nausea, and vomiting. Metaxalone is generally not recommended for people with a known tendency to become anemic, and who have kidney or liver disease. Metaxalone may affect blood sugar tests for people with diabetes. The FDA has not rated metaxalone for safety during pregnancy.
      • Methocarbamol (Robaxin, Robaxin-750). Methocarbamol eases acute muscle and bone pain. It can be taken as a tablet or by injection. Common side effects include dizziness, headache, nausea, flushing, and blurred vision. Methocarbamol is generally not recommended to people with renal disease or failure, or a history of allergic reaction to the medication. The FDA has given methocarbamol a C rating for safety during pregnancy.
      • Orphenadrine. Orphenadrine is a medication used to relieve pain and stiffness caused by muscle injuries. It is available as an extended-release tablet. Common side effects include dry mouth, lightheadedness, difficult urination, heartburn, nausea and vomiting. It is generally not recommended to people with previous sensitivities to the ingredients, myasthenia gravis, those with glaucoma or certain types of ulcers. The FDA has given orphenadrine a C rating for safety during pregnancy.
      • Tizanidine (Comfort Pac with Tizanidine, Zanaflex). Tizanidine is used to treat muscle spasms caused by spinal cord injuries and other conditions such as multiple sclerosis. Tizanidine is available in tablet and capsule form and absorbs differently depending on whether it is taken on an empty stomach or with food. Common side effects include dry mouth, dizziness, constipation and tiredness. It should not be used by people taking fluvoxamine or ciprofloxacin or those who have liver disease. Tizanidine is rated in the C category for safety during pregnancy.

Sometimes the first muscle relaxers a doctor prescribes does not work as well as expected. It may be necessary to try an alternative if the initial prescription is not effective. Many drugs interact with muscle relaxers and a person should keep their health care provider informed of all prescription and non-prescription medications he or she is taking.

There is very little research regarding which muscle relaxers are most effective, so the choice of which medication—or whether to use one at all—is based on factors such as a person’s reaction to the medication and personal preferences, potential for abuse, possible drug interactions, and adverse side effects.

What is the important information I should know before I take Cyclobenzaprine ?

You should not use cyclobenzaprine if you are allergic to it, or if you have:

      • a thyroid disorder;
      • heart block, heart rhythm disorder, congestive heart failure; or
      • if you have recently had a heart attack.

Cyclobenzaprine is not approved for use by anyone younger than 15 years old.

Do not use cyclobenzaprine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine.

Some medicines can interact with cyclobenzaprine and cause a serious condition called serotonin syndrome. Be sure your doctor knows if you also take stimulant medicine, opioid medicine, herbal products, or medicine for depression, mental illness, Parkinson’s disease, migraine headaches, serious infections, or prevention of nausea and vomiting. Ask your doctor before making any changes in how or when you take your medications.

Tell your doctor if you have ever had:

      • liver disease;
      • glaucoma;
      • enlarged prostate; or
      • problems with urination.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

Older adults may be more sensitive to the effects of this medicine.

HOW SHOULD I TAKE CYCLOBENZAPRINE?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Cyclobenzaprine is usually taken once daily for only 2 or 3 weeks. Follow your doctor’s dosing instructions very carefully.

Swallow the capsule whole and do not crush, chew, break, or open it.

Take the medicine at the same time each day.

Call your doctor if your symptoms do not improve after 3 weeks, or if they get worse. Store at room temperature away from moisture, heat, and light.

Cyclobenzaprine Medline Plus Drug Information

Why is this medication prescribed?

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 this medicine 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.

Other uses for this medicine

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

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 side effects can this medication cause?

Cyclobenzaprine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • dry mouth
  • dizziness
  • nausea
  • constipation
  • heartburn
  • extreme tiredness

If you experience any of the following symptoms, call your doctor immediately:

  • skin rash
  • hives
  • swelling of the face or tongue
  • difficulty breathing or swallowing
  • irregular or fast heart rate
  • chest pain

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

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:

  • 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

What other information should I know?

Keep all appointments with your doctor.

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

  • Amrix®
  • Flexeril®

This branded product is no longer on the market. Generic alternatives may be available.

Last Revised – 02/15/2017