Skip to main content
NCBI home page
Canadian Family Physician logoLink to Canadian Family Physician
. 2015 Dec;61(12):1074.

Cyclobenzaprine for acute back pain

Emélie Braschi 1, Scott Garrison 1, G Michael Allan 1
PMCID: PMC4677944  PMID: 26668287

Clinical question

How effective is cyclobenzaprine for acute back pain?

Bottom line

Cyclobenzaprine reduces pain and leads to global improvement compared with placebo for 1 in every 3 to 9 patients in the first week. Cyclobenzaprine generally adds little to naproxen. Taken 3 times daily, 5 mg is as effective as 10 mg, with less somnolence.

Evidence

  • In 3 systematic reviews (9 to 46 RCTs, 820 to 5401 patients) of non-benzodiazepine muscle relaxants versus placebo, differences were statistically significant1–3:

    • –Pain scores were about 12 points lower on a 100-point visual analogue scale at 10 days.1

    • –There was undefined pain reduction (number needed to treat [NNT] of 4 to 7) at 2 to 7 days; an undefined target for global efficacy (NNT = 4) was achieved at 2 to 4 days.2

  • Cyclobenzaprine versus placebo:

    • –One systematic review (14 RCTs, 3023 patients) showed global improvement (NNT = 3) at about 10 days.4

    • –We pooled data from 2 publications with 2 RCTs each.

      • —Pain relief (1389 patients) was achieved at 7 days in 50% of those taking 5 mg of cyclobenzaprine 3 times daily versus 38% taking placebo (NNT = 9; P < .001).5 No difference was noted in 5 mg versus 10 mg or 2.5 mg versus placebo.

      • —No difference was noted between 30 mg extended release once daily and 10 mg immediate release 3 times daily (504 patients).6

  • An RCT of cyclobenzaprine plus ibuprofen (867 patients) showed no benefit to adding ibuprofen.7

  • An RCT of naproxen plus cyclobenzaprine (323 patients) showed no benefit to adding cyclobenzaprine at day 7, but only about 30% had frequent or continual back pain then.8

Context

  • Most trials were industry sponsored; had small samples, short durations, and poorly defined targets; and were unclear about whether cutoffs were clinically meaningful.4

  • No differences in efficacy were seen among the muscle relaxants, although cyclobenzaprine was more consistently evaluated.3 Cyclobenzaprine is equal or superior to diazepam.3 Other direct comparisons are lacking.

  • Adverse events include dose-related somnolence and dry mouth. Somnolence occurred in 10% of those taking placebo, 29% taking 5 mg 3 times daily, and 38% taking 10 mg 3 times daily.5

    • –Taken 3 times daily, 10 mg caused more somnolence than 5 mg (number needed to harm of 12).

    • –Rates of discontinuation owing to somnolence were 0.8% for placebo, 2.5% for 5 mg 3 times daily, and 5.2% for 10 mg 3 times daily.5

  • Guidelines recommend cyclobenzaprine for the treatment of acute low back pain.9

Implementation

About 50% to 90% of people will have back pain; about 90% of those cases will be nonspecific.9 X-ray scans are discouraged for acute nonspecific back pain.10 For acute back pain, acetaminophen is no better than placebo11; NSAIDs provide global improvement for 1 in every 11 patients compared with placebo.12 Cyclobenzaprine is structurally similar to tricyclic antidepressants and has similar adverse events. It should be avoided in the elderly13 and be given as 5 mg. While muscle relaxants have abuse potential,14 we did not find studies describing abuse of cyclobenzaprine.

Footnotes

The opinions expressed in Tools for Practice articles are those of the authors and do not necessarily mirror the perspective and policy of the Alberta College of Family Physicians.

References

  • 1.Machado LA, Kamper SJ, Herbert RD, Maher CG, McAuley JH. Analgesic effects of treatments for non-specific low back pain: a meta-analysis of placebo-controlled randomized trials. Rheumatology (Oxford) 2009;48(5):520–7. [DOI] [PubMed] [Google Scholar]
  • 2.Van Tulder MW, Touray T, Furlan AD, Solway S, Bouter LM. Muscle relaxants for nonspecific low back pain. Cochrane Database Syst Rev 2003;(2):CD004252. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Chou R, Peterson K, Helfand M. Comparative efficacy and safety of skeletal muscle relaxants for spasticity and musculoskeletal conditions: a systematic review. J Pain Symptom Manage 2004;28(2):140–75. [DOI] [PubMed] [Google Scholar]
  • 4.Browning R, Jackson JL, O’Malley PG. Cyclobenzaprine and back pain: a meta-analysis. Arch Intern Med 2001;161(13):1613–20. [DOI] [PubMed] [Google Scholar]
  • 5.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):1056–73. [DOI] [PubMed] [Google Scholar]
  • 6.Malanga GA, Ruoff GE, Weil AJ, Altman CA, Xie F, Borenstein DG. Cyclobenzaprine ER for muscle spasm associated with low back and neck pain: two randomized, double-blind, placebo-controlled studies of identical design. Curr Med Res Opin 2009;25(5):1179–96. [DOI] [PubMed] [Google Scholar]
  • 7.Childers MK, Borenstein D, Brown RL, Gershon S, Hale ME, Petri M, et al. Low-dose cyclobenzaprine versus combination therapy with ibuprofen for acute neck or back pain with muscle spasm: a randomized trial. Curr Med Res Opin 2005;21(9):1485–93. [DOI] [PubMed] [Google Scholar]
  • 8.Friedman BW, Dym AA, Davitt M, Holden L, Solorzano C, Esses D, et al. Naproxen with cyclobenzaprine, oxycodone/acetaminophen, or placebo for treating acute low back pain: a randomized clinical trial. JAMA 2015;314(15):1572–80. [DOI] [PubMed] [Google Scholar]
  • 9.Guideline for the evidence-informed primary care management of low back pain. 2nd ed. Edmonton, AB: Toward Optimized Practice; 2011. [Google Scholar]
  • 10.Allan GM, Spooner GR, Ivers N. X-ray scans for nonspecific low back pain. A nonspecific pain? Can Fam Physician 2012;58:275. [PMC free article] [PubMed] [Google Scholar]
  • 11.Williams CM, Maher CG, Latimer J, McLachlan AJ, Hancock MJ, Day RO, et al. Efficacy of paracetamol for acute low-back pain: a double-blind, randomised controlled trial. Lancet 2014;384(9954):1586–96. [DOI] [PubMed] [Google Scholar]
  • 12.Roelofs PD, Deyo RA, Koes BW, Scholten RJ, van Tulder MW. Non-steroidal anti-inflammatory drugs for low back pain. Cochrane Database Syst Rev 2008;(1):CD000396. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Spence MM, Shin PJ, Lee EA, Gibbs NE. Risk of injury associated with skeletal muscle relaxant use in older adults. Ann Pharmacother 2013;47(7–8):993–8. [DOI] [PubMed] [Google Scholar]
  • 14.Reeves RR, Ladner ME, Perry CL, Burke RS, Laizer JT. Abuse of medications that theoretically are without abuse potential. South Med J 2015;108(3):151–7. [DOI] [PubMed] [Google Scholar]

Articles from Canadian Family Physician are provided here courtesy of College of Family Physicians of Canada

RESOURCES