How Do Skeletal Muscle Relaxants Fit Into Pain Management?

Centrally acting skeletal muscle relaxers (SMRs) include drugs as a baclofen, sold under the brand names Gablofen and Loresal; carisoprodol, sold under the name Soma; and metaxalone, sold under the name Metaxall. Long-term use of SMRs may provide relief for certain pain syndromes according to a recent systematic review published in JAMA Network Open. Those who suffer from painful spasms, cramps, and neck pain may benefit. With increasing concerns over opioid prescriptions and their associated risks, SMRs may offer an alternative for managing chronic pain.

Recent guidance from the CDC’s Clinical Practice Guideline for Prescribing Opioids for Pain and the HHS’ National Pain Strategy called for pain management strategies that encourage nonopioid pharmacologic treatment options. SMRs are also listed as a therapeutic option in the American College of Physicians clinical practice guidelines for treating low back pain.

Skeletal muscle relaxant prescribing trends and physician visits for muscle relaxants increased over an 11-year period from 2005 to 2016. A major reason are prescriptions for nonspecific back pain. But about one-third of SMR prescriptions are for nonback pain syndromes, suggesting SMRs are being used off-label or for indications where clinical evidence is lacking.

Benjamin Oldfield, M.D.,from the Yale School of Medicine, and his colleagues assessed the effectiveness, safety and implications of using SMRs for extended periods, greater than four weeks, to manage chronic pain conditions.

An extensive database search had five inclusion criteria: patients with painful syndromes lasting three months or more; SMR use equal to or greater than four weeks; an acceptable comparison such as a placebo or nonpharmacologic treatment; quality of life and outcomes related to pain; and if the study was a randomized clinical trial or cohort study involving at least 10 participants.The authors identified 44 articles that met all the criteria for inclusion in the systematic review. Of the 44 articles, 30 were randomized controlled trials, and 14 were cohort studies.

Not surprisingly, their review found that SMRs are more effective when pain originates from muscle spasms and cramps.

But for conditions in which the root of pain may have less muscular involvement, such as fibromyalgia, headaches and low-back pain, the evidence suggested fewer clinical benefits. And SMRs for pain from osteoarthritis, cervical pain, neuropathic pain and cancer-related pain on balance did not demonstrate therapeutic benefit.

In light of evidence suggesting increased utilization of SMR prescriptions to patients with chronic pain in addition to existing opioid usage, Oldfield and his colleagues expressed strong concern about the risks of opioid-related adverse events, including overdose. Given the limited evidence of efficacy from this study for SMRs in long-term pain management, the increasing demand for SMRs to manage pain is concerning. This research builds on existing systematic reviews that have found no evidence of clinically significant benefit of SMRs over placebo in acute and chronic nonspecific pain management.

Given the increasing prevalence of chronic pain conditions globally, understanding the efficacy and safety of these medications is crucial for healthcare practitioners. Furthermore, analyzing specific conditions allows for more tailored therapeutic strategies, improving patient outcomes.