Muscle relaxants may provide benefits for a narrow segment of chronic pain conditions

Key takeaways:

• In 44 studies, muscle relaxants showed benefit for only a small subset of pain syndromes.
• The findings suggest physicians should consider deprescribing if pain-related goals are not met.

Long-term use of skeletal muscle relaxants may be beneficial only for the treatment of a narrow subset of chronic pain conditions, according to the findings of a systematic review published in JAMA Network Open.

Findings from the analysis suggest that skeletal muscle relaxants may effectively treat painful cramps, spasms and neck pain, while showing no superior ability to relieve symptoms related to other chronic pain syndromes.

According to Benjamin J. Oldfield, MD, MHS, from Yale School of Medicine, and colleagues, prescriptions of skeletal muscle relaxants doubled between 2005 and 2016, while physician visits for continuing prescriptions tripled during that time.

Because of that growth and the fact that one-third of patients prescribed skeletal muscle relaxants do not have a preceding musculoskeletal disorder diagnosis, “a broader examination of their long-term use for multiple chronic conditions is needed,” they wrote .

In the analysis, the researchers searched several online databases and compiled data from 30 randomized controlled trials (n = 1,314) and 14 cohort studies (n = 1,168 participants) that assessed skeletal muscle relaxants for several types of chronic pain conditions, including fibromyalgia, neck pain, low back pain and headaches.

The typically short studies lasted between 4 and 6 weeks and represented nine specific skeletal muscle relaxants. Meanwhile, the researchers characterized the randomized controlled trials included in the study as having low to moderate risk for bias and the quality of the cohort studies as fair to good.

Oldfield and colleagues found that the effectiveness of skeletal muscle relaxants appeared strongest when used for neck pain, painful cramps and trigeminal neuralgia.

The evidence suggested that skeletal muscle relaxants for low back pain, headaches, fibromyalgia and other syndromes did not provide additional clinical benefits when compared with placebo.

The most common adverse effects of skeletal muscle relaxants included dry mouth and sedation.

The short length of the studies “may bias toward higher efficacy and toward lower adverse effects,” the researchers wrote.

They explained that the finding that skeletal muscle relaxants may benefit only a small subset of pain syndromes raises concerns due to the treatments’ large growth and prevalence in the past decade.

“For patients already prescribed long-term [skeletal muscle relaxants], interventions are needed to assist clinicians to engage in shared decision-making with patients about deprescribing [skeletal muscle relaxants],” they wrote. “This may be particularly true for older patients, for whom risks of adverse events may be greater.”

They added that academic detailing and tapering guidelines, “which have shown some success in deprescribing of opioids and other medications,” could help inform interventions.

The researchers identified multiple limitations in the study. For example, the analysis included only studies published in English, Spanish and Italian.

The review also excluded qualitative studies, even though they could offer insight into patient experiences and care processes, “which are particularly important in pain management,” the researchers wrote.

Ultimately, “clinicians should be vigilant for adverse effects and consider deprescribing if pain-related goals are not met,” Oldfield and colleagues concluded.