Deprecated: Return type of DrupalCacheArray::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/rprlib/prod72/www/includes/bootstrap.inc on line 362
Deprecated: Return type of DrupalCacheArray::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/rprlib/prod72/www/includes/bootstrap.inc on line 369
Deprecated: Return type of DrupalCacheArray::offsetSet($offset, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/rprlib/prod72/www/includes/bootstrap.inc on line 381
Deprecated: Return type of DrupalCacheArray::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/rprlib/prod72/www/includes/bootstrap.inc on line 388 University of Oklahoma Health Sciences Center
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 695 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 696 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 697 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 700 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_environment_initialize() (line 702 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 328 of /home/rprlib/prod72/www/sites/default/settings.php).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 329 of /home/rprlib/prod72/www/sites/default/settings.php).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 337 of /home/rprlib/prod72/www/sites/default/settings.php).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in include_once() (line 344 of /home/rprlib/prod72/www/sites/default/settings.php).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_settings_initialize() (line 819 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in drupal_settings_initialize() (line 828 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Warning: session_name(): Session name cannot be changed after headers have already been sent in drupal_settings_initialize() (line 831 of /home/rprlib/prod72/www/includes/bootstrap.inc).
Deprecated function: Return type of DatabaseStatementBase::execute($args = [], $options = []) should either be compatible with PDOStatement::execute(?array $params = null): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2244 of /home/rprlib/prod72/www/includes/database/database.inc).
Deprecated function: Return type of DatabaseStatementEmpty::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
Deprecated function: Return type of DatabaseStatementEmpty::next() should either be compatible with Iterator::next(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
Deprecated function: Return type of DatabaseStatementEmpty::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
Deprecated function: Return type of DatabaseStatementEmpty::valid() should either be compatible with Iterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
Deprecated function: Return type of DatabaseStatementEmpty::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in require_once() (line 2346 of /home/rprlib/prod72/www/includes/database/database.inc).
Importance: Stricter opioid prescribing guidelines have increased prescriptions of skeletal muscle relaxants (SMRs) for chronic pain, but the efficacy of long-term use of SMRs for chronic pain is unknown.
Objective: To systematically review the effectiveness or efficacy of long-term use of SMRs for chronic pain.
Evidence review: Two reviewers systematically searched Ovid MEDLINE, Embase (Ovid), Web of Science, CINAHL, and Cochrane through December 4, 2023. They included articles published in English, Spanish, or Italian. Only randomized clinical trials (RCTs) and cohort studies with comparator groups evaluating at least 1-month duration of SMRs for chronic pain were included. The reviewers dually reviewed data abstraction, risk-of-bias, and quality. They characterized studies by chronic pain syndrome: low back pain, fibromyalgia, headaches, painful cramps or spasticity, and other syndromes.
Findings: A total of 30 RCTs with 1314 participants and 14 cohort studies with 1168 participants assessed SMRs for chronic pain. Studies were primarily short-term (4-6 weeks). Nine unique SMRs were represented by the studies identified. Eleven studies (25%) examined baclofen, 8 (18%) examined tizanidine, and 7 (16%) examined cyclobenzaprine. Evidence for effectiveness was strongest for SMRs used for trigeminal neuralgia, neck pain, and painful cramps; evidence suggested SMRs for fibromyalgia, low back pain, and other syndromes were not more beneficial than placebo. The most common adverse effects were sedation and dry mouth. RCTs had a low to moderate risk of bias, and the quality of cohort studies was fair to good.
Conclusions and relevance: In this systematic review of long-term use of SMRs for chronic pain, findings suggest that their long-term use may benefit patients with painful spasms or cramps and neck pain; their long-term use for low back pain, fibromyalgia, and headaches did not appear to be beneficial. Clinicians should be vigilant for adverse effects and consider deprescribing if pain-related goals are not met.
