— Spike in prescriptions among older adults particularly concerning, researchers note

by Elizabeth Hlavinka, Staff Writer, MedPage Today June 24, 2020

As U.S. opioid prescriptions continue to trend downwards, skeletal muscle relaxer scripts are on the rise, according to an analysis of the CDC’s National Ambulatory Medical Care Survey (NAMCS).

Between 2005 and 2016, the number of office visits in which muscle relaxers were prescribed, most commonly for back pain and musculoskeletal conditions, doubled from 15.5 million to 30.7 million, reported Charles E. Leonard, PharmD, MSCE, of the University of Pennsylvania in Philadelphia, and colleagues.

While office visits resulting in new skeletal muscle relaxer prescriptions during this period remained relatively stable at about six million per year, visits for continued therapy tripled from 8.5 million to 24.7 million, the researchers wrote in JAMA Network Open.

The proportion of older adults receiving muscle relaxant prescriptions increased three-fold across the study period such that by 2016, adults over 65 accounted for 22.2% of visits in which a muscle relaxant was prescribed, the team added. Also, 67.2% of continued muscle relaxant visits in 2016 were completed while the patient was on concomitant opioids.

“For a number of years now, the American Geriatrics Society has warned providers of prescribing skeletal muscle relaxers for older adults, and the long-term treatment with skeletal muscle relaxers was particularly concerning to us because most of the available data really only support short-term use of these drugs,” Leonard told MedPage Today, adding that in some cases, especially among younger people, the drugs may be considered.

Nationally, opioid prescriptions decreased by about 20% between 2006 and 2017, in part due to the CDC’s 2016 guidelines on opioid prescribing. Between 2015 and 2018, close to 11% of adults reported being on at least one pain medication prescription, and 6% said they were on opioids, per CDC data.

Weighing the Risks-Benefit of Skeletal Muscle Relaxants

Since muscle relaxant side effects tend to be less severe than the adverse events associated with opioids, they may have been used to replace opioids for some chronic pain patients, commented Samer Narouze, MD, PhD, of Western Reserve Hospital in Cuyahoga Falls, Ohio, who wasn’t involved with the research.

“If the rate of muscle relaxant prescriptions is increasing, but this is accompanied by a waning of opioids, it would be a welcome thing because you are replacing an evil with a lesser evil,” Narouze told MedPage Today. “In the end, you are helping the patient.”

While the steady rate of new muscle relaxant prescriptions is “encouraging,” the increased rate of long-term use observed in this study is “concerning,” said Stephen Saklad, PharmD, BCPP, of the University of Texas at Austin and also not involved in the research.

“Even acutely, [muscle relaxers] are only moderately effective and have significant adverse effects in many people,” Saklad told MedPage Today in an email. “The increasing combination with opioids suggests ineffectiveness and is a problematic practice due to greatly increased adverse effects.”

Skeletal muscle relaxants can augment the central nervous system side effects and respiratory depression from opioids and benzodiazepines, and also carry an increased risk of falling for elderly patients, Narouze said.

Leonard said that although benzodiazepines were not in the top 10 list of concomitant medications prescribed along with skeletal muscle relaxers in this study, lorazepam and alprazolam were still concomitantly prescribed in hundreds of thousands of cases.

However, since the study did not collect data on clinical outcomes associated with muscle relaxant prescribing, such as emergency room visits coded for falls, it is unclear how many of these prescriptions resulted in negative outcomes for patients, Narouze said.

“The take-home message here is that muscle relaxers are being overprescribed and we need to be aware they are not really innocent medication,” he added.

Study Details, Further Findings

For the study, Leonard and co-authors collected data on ambulatory care visits from the NAMCS involving prescriptions of baclofen, carisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, orphenadrine, and tizanidine.

The nearly 315 million office visits in the database formed a cohort that was a mean 53.5 years old and 61.8% of whom were male. Patient characteristics were similar across the study period and a snapshot of the 2016 cohort of 30,730,262 patients prescribed muscle relaxants was made up of 58.2% who were female. A majority were white (53.7%), 10.2% were African American, 1.2% were Asian, and 2.2% were Native American or Alaska Native.

In 2016, the proportion of patients receiving muscle relaxers was highest among older adults, followed by adults ages 45-64 (48.5%), 25-44 (24.9%), 15-24 (4.1%), and adolescents under 15 (0.3%), the researchers reported. This age distribution was similar across all years of the study.

Specifically among older adults, the number of prescriptions for muscle relaxer agents that are considered to be potentially inappropriate for this age group — carisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, and orphenadrine — nearly doubled from 2.2 million to 4.3 million across the study period, Leonard and co-authors added.

The most commonly prescribed concomitant therapy was hydrocodone-acetaminophen, followed by ibuprofen, naproxen, and tramadol.

Geographically, the most dramatic changes in muscle relaxant prescriptions observed across the study period occurred in the Northeast, where new muscle relaxant visits decreased by about 33% and continued visits increased by 325%. This pattern was similar but less pronounced in the South and the Midwest, and in the West, new and continued visits increased by 5.4% and 91.6%, respectively, the authors reported.

The study did not account for hospital visits resulting in a muscle relaxant prescription and did not include data on off-label use of muscle relaxers, which are limitations, Leonard said. There was also no way to track patients longitudinally using this dataset, he and his co-authors added.