Muscle relaxants for acute low back pain
Date First Published:
April 13, 2005
Last Updated:
July 5, 2005
Report by:
Simon Carley, Consultant in Emergency Medicine (Manchester Royal Infirmary)
Three-Part Question:
[In patients with simple acute low back pain] are [muscle relaxants better than placebo] at [decreasing pain, improving mobility and speeding a return to normal activities (e.g. work)]
Clinical Scenario:
A 35 year old woman presents to the emergency department with acute lower back pain radiating to her right buttock. Neurological examination is normal and there are no "red flag" symptoms or signs to suggest that this is anything other than simple low back pain. You treat her with oral paracetamol and voltarol and return to review her later. She is still in pain and appears to get a lot of spasm when she tries to get up. You suggest a course of diazepam to act as a muscle relaxant but your registrar says that it is a waste of time and to get her going quick as it is 3 hours since she arrived in the department.
Search Strategy:
[muscle relaxant$ or exp muscle relaxants, central/ or antispasticity.mp or benzodiazepines.mp or exp.BENZODIAZEPINES or antispasmodic.mp. or exp Parasympatholytics/] and [back pain.mp or exp back pain/ or exp low back pain or lumbar pain.mp]
Search Details:
OVID Medline on the www. via ATHENS 1966-2005
Outcome:
One high quality systematic review was found from 2003 which searched up until October 2001. The Medline search was therefore restricted to after October 2001 to identify anuy new papers not in the systematic review.
Medline: 57 papers were found of which 3 were relevant to the clinical question
Medline: 57 papers were found of which 3 were relevant to the clinical question
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Muscle relaxants for nonspecific low back pain: A systematic review within the framework of the Cochrane Collaboration van Tulder MW, Touray T, Furlan AD, Solway S, Bouter LM. 2003 Canada | Review of papers examining the use of muscle relaxants in patients with simple low back pain. Only RCTs and CCTs were included in the article. | Systematic review | Benzodiazepine vs placebo in acute back pain | One low quality trial. Benefit in use of benzodiazepines. | This is a well conducted review article. There is also a Cochrane review by the same authors on the same subject. The outcomes in individual trials are often disparate making grouping of results difficult. |
| Nonbenzodiazepines vs placebo in acute back pain | 4 trials (3 high quality, 1 low quality) showed benefit to muscle relaxants in short term pain relief , global efficiency and physical outcome. | ||||
| Side effects in acute lower back pain | All trials showed clinically and statistically significant increases in side effects of muscle relaxants (e.g. drowsiness, dizziness) | ||||
| Antispasticity drugs for acute low back pain | 2 high quality trials both demonstrated a benefit in acute low back pain | ||||
| Muscle relaxants + analgesics/NSAIDS vs. placebo + analgesics/NSAIDS in acute back pain | 3 trials. Benefit in use of muscle relaxants but a significant increase in side effect reporting. | ||||
| Injection therapy | Strong evidence of benefit in acute back pain | ||||
| The use of muscle relaxant medication in acute low back pain Bernstein E, Carey TS, Garrett JM. 2004 USA | 1633 patients with low back pain. Recruited from community practitioners. Observed to determine if the use of muscle relaxants was associated with a more rapid recovery. No interventions were made by the authors on the care of the patients. | Observational cohort. | Baseline data on patient mix | 24% had sciatica. average pain was 5.4 on a 10 point scale. Average Roland baseline score was 11.2. Mean time to functional recovery (if recovered) was 16.2 days. | Only looked at time to return to normal function. benefit in treatment may be in relief of symptoms only which would be missed on this study. Purely observational study which is prone to a great deal of bias. Groups clearly different at baseline with users of muscle relaxants apparently having a greater degree of illness (though this is adjusted for in the Cox analysis) |
| Use of muscle relaxants | 49% of patients used muscle relaxants | ||||
| Statistically significant differences in patient characteristics between users and non users | Users were on average 2.3 years younger (p=0.012); female 50% vs 45%; on workers compensation 34% vs 28%; or if they had a higher pain score, roland disability score or if they took longer to recover. They were less likely to be used if the patient had seen a chiropracter as initial provide 18% vs 55%; | ||||
| Time to achieve functional recovery on Cox proportional hazards model. | No difference in recovery rates between those using muscle relaxants and those not. | ||||
| A randomized clinical trial comparing chiropractic adjustments to muscle relaxants for subacute low back pain. Hoiriis KT, Pfleger B, McDuffie C, Cotsonis MA, Elsangak O, Hinson R, Verzosa GT. 2004 Switzerland | 192 patients with back pain of 2-6 weeks duration. Randomised to either chiropractic plus placebo, relaxant plus sham chiro or sham both. Followed up for 4 weeks. | PRCT | VAS for pain | All groups reduced significantly. No statistical difference between groups. | Difficult to produce a sham chiropractic but the authors have tried hard to do so in this study. |
| Oswestry disability index | All groups reduced significantly. No statistical difference between groups. | ||||
| Modified Zung | All groups reduced significantly. No statistical difference between groups. | ||||
| Schobers test | No group significantly improved flexibility. No statistical difference between groups. |
Author Commentary:
Acute back pain is a common problem in emergency medicine and general practice. Whilst the majority of patients seem to cope well with advice and simple analgesics many complain of spasmodic pain and stiffness. There therefore appears to be a logical argument for the use of muscle relaxants. This is supported by the papers in the table.
The systematic review demonstrates that in RCTs and CCTs there does appear to be a real benefit from the use of muscle relaxants in the acute and chronic settings. However, the incidence of side effects is considerable and thei blanket use cannot be advocated. It will remain up to the treating physician to assess the need for and the potential risks in individual patients
The systematic review demonstrates that in RCTs and CCTs there does appear to be a real benefit from the use of muscle relaxants in the acute and chronic settings. However, the incidence of side effects is considerable and thei blanket use cannot be advocated. It will remain up to the treating physician to assess the need for and the potential risks in individual patients
Bottom Line:
Muscle relaxants are effective in the management of acute and chronic back pain. However, the incidence of side effects means that they must be used with caution.
Level of Evidence:
Level 1: Recent well-done systematic review was considered or a study of high quality is available
References:
- van Tulder MW, Touray T, Furlan AD, Solway S, Bouter LM.. Muscle relaxants for nonspecific low back pain: A systematic review within the framework of the Cochrane Collaboration
- Bernstein E, Carey TS, Garrett JM.. The use of muscle relaxant medication in acute low back pain
- Hoiriis KT, Pfleger B, McDuffie C, Cotsonis MA, Elsangak O, Hinson R, Verzosa GT.. A randomized clinical trial comparing chiropractic adjustments to muscle relaxants for subacute low back pain.