Cyclobenzaprine

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 drugs 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 the 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 the 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

Renal impairment

• Not studied

Common side effects include:

• drowsiness
• dizziness
• dry mouth
• tiredness
• hoarseness
• headache
• fatigue
• rapid or irregular heartbeat
• bad taste in your mouth
• indigestion
• blurred vision
• constipation
• lack of energy or physical weakness
• confusion
• nausea
• nervousness
• irregular heartbeat
• low blood pressure
• fainting
• rapid heartbeat
• widening of blood vessels
• hepatitis
• yellow skin or eyes (jaundice)
• immune hypersensitivity reaction

Rare side effects of Cyclobenzaprine include:

• abnormal heartbeat
• reduction or stoppage of bile flow
• acute allergic reaction

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

Severe Interactions of Cyclobenzaprine include:

• isocarboxazid
• phenelzine
• tranylcypromine

Cyclobenzaprine has moderate interactions with at least 43 different drugs.

Cyclobenzaprine has mild interactions with at least 221 different drugs.

Minor interactions of Cyclobenzaprine include:

• desipramine
• dimenhydrinate
• donepezil
• eucalyptus
• galantamine
• sage
• tacrine
• trazodone

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

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

Contraindications

• 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

Effects of Drug Abuse

• May cause drowsiness/dizziness; do not ingest alcohol or other central nervous system depressants as it may impair the ability to operate heavy machinery

Short-Term Effects

• May cause drowsiness/dizziness; do not ingest alcohol or other central nervous system depressants as it may impair the ability to operate heavy machinery
• See "What Are Side Effects Associated with Using Cyclobenzaprine?"

Long-Term Effects

• Cyclobenzaprine use is only recommended for short periods, 2-3 weeks
• See "What Are Side Effects Associated with Using Cyclobenzaprine?"

Cautions

• 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 the ability to operate heavy machinery
• May take with food to avoid stomach upset
• Serotonin syndrome is 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 the 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

Pregnancy and Lactation

• 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