Cyclobenzaprine

- 5, 7.5 and 10mg tablets PO (immediate release)

- 10, 15 and 30 mg tablets PO (extended release)

Emergency Medicine Executive Summary

(Updated November 2022)

Ciclobenzaprine is a centrally acting skeletal muscle relaxant widely prescribed to relieve acute painful musculoskeletal conditions as an adjunct treatment to physical therapy and rest. It is also used as a temporary adjuvant medication along with non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen.

  • Limited data supports its use in the short term for treating acute muscle spasm, acute low back pain, fibromyalgia and temporomandibular disorder (1, 2, 3, 4).

  • Muscle relaxants including cyclobenzaprine have significant adverse effects on the central nervous system (sedation, drowsiness, dizziness), therefore, they should be prescribed with caution and their benefits need to be balanced with their risks; experts differ on whether they should be used or not (2, 3, 6, 7).

  • It has a similar structure to tricyclic antidepressants such as amitriptyline, thus it can cause serious anticholinergic effects, but no direct cardiotoxicity has been reported in cases of overdose (eg. sodium channel blockade and QRS complex widening)(5).

Indications

US-FDA Labeled

  • Adjunct to rest and physical therapy to relieve muscle spasms associated with acute, painful musculoskeletal conditions for short term use (8)

Non-US-FDA Labeled

  • Fibromyalgia

  • Myofascial pain due to temporomandibular disorders

Adult dose

Adult dose for acute painful musculoskeletal spasms (8)

  • Immediate release formulation:

    • 5mg TID with one dose at night.

    • Maximum 30mg/day, up to 2-3 weeks.

  • Extended release formulation:

    • 10-15mg once daily at bedtime.

    • Maximum 30mg/day, up to 2-3 weeks.

  • Many clinicians start at a low dose at night (5mg) and then titrate up if it is strictly necessary.

Pediatric dose

  • Safety and effectiveness in pediatric patients below 15 years old have not been established (8).

  • Pediatric use of cyclobenzaprine is not approved and not recommended.

Renal, hepatic and geriatric adjustments

  • Renal: no dosage adjustment needed in mild to severely altered kidney function, but use with caution due to limited safety and efficacy data (8).

  • Hepatic: plasmatic concentration of cyclobenzaprine is increased in patients with hepatic impairment. Use with caution in mild impairment (5 mg, immediate release, titrate solely upward). Due to the lack of data in subjects with more severe hepatic insufficiency, the use of cyclobenzaprine hydrochloride is not recommended (8).

  • Geriatric: use of muscle relaxants in older adults is not recommended because of anticholinergic effects, sedation, as well as an increased risk of falls and fractures. Their use also has a questionable effectiveness at dosages tolerated by this population. (9). If strictly necessary, it should be initiated with a 5 mg dose and titrated slowly upward (8).

References

  1. Herman CR, Schiffman EL, Look JO, Rindal DB. The effectiveness of adding pharmacologic treatment with clonazepam or cyclobenzaprine to patient education and self-care for the treatment of jaw pain upon awakening: a randomized clinical trial. J Orofac Pain. 2002;16(1):64-70.
    Pubmed

  2. Borenstein DG, Korn S. Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials. Clin Ther. 2003;25(4):1056-1073. doi:10.1016/s0149-2918(03)80067-x
    Pubmed

  3. Van Tulder MW, Touray T, Furlan AD, Solway S, Bouter LM. Muscle relaxants for non-specific low back pain. Cochrane Database Syst Rev. 2003;2003(2):CD004252. doi:10.1002/14651858.CD004252
    Pubmed

  4. Tofferi JK, Jackson JL, O'Malley PG. Treatment of fibromyalgia with cyclobenzaprine: A meta-analysis. Arthritis Rheum. 2004;51(1):9-13. doi:10.1002/art.20076
    Pubmed

  5. Bebarta VS, Maddry J, Borys DJ, Morgan DL. Incidence of tricyclic antidepressant-like complications after cyclobenzaprine overdose. Am J Emerg Med. 2011;29(6):645-649. doi:10.1016/j.ajem.2010.01.014
    Pubmed

  6. Edlow JA. Managing Nontraumatic Acute Back Pain. Ann Emerg Med. 2015;66(2):148-153. doi:10.1016/j.annemergmed.2014.11.011
    Pubmed

  7. Walls RM, Hockberger RS, Gausche-Hill M. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th edition. Philadelphia, PA: Elsevier; 2018.
    Elsevier

  8. NIH-NLM (National Institutes of Health - National Library of Medicine). DailyMed. Label: Cyclobenzaprine Hydrochloride tablet, film coated. Updated in December 2018.
    DailyMed

  9. American Geriatrics Society Beers Criteria® Update Expert Panel. American Geriatrics Society 2019 Updated AGS Beers Criteria® for Potentially Inappropriate Medication Use in Older Adults. J Am Geriatr Soc. 2019;67(4):674-694. doi:10.1111/jgs.15767
    Pubmed

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