Centrally Acting Skeletal Muscle Relaxants and Associated Drugs

Severity of ineffective esophageal motility is associated with utilization of skeletal muscle relaxant medications

“…Cyclobenzaprine is thought to act at the level of the brainstem, and has also been proposed to act as a 5‐HT 2 receptor antagonist in the spinal cord . While the exact mechanism of action of Metaxalone and Methacarbamol remains unknown, both are similarly thought to act as general CNS depressants with resulting depression of motor neuron activity, without a direct effect on skeletal muscle . Tizanidine, an alpha‐2 adrenergic agonist, acts both supraspinally and at the level of the spinal cord .…”

“…Skeletal muscle relaxants as a class of drugs have been associated with numerous side effects, with fatigue being the most common, and with multiple GI side effects such as nausea, vomiting and epigastric discomfort . Cyclobenzaprine and Tizaindine may cause dysphagia through their depressive effect on the CNS, which may decrease awareness and voluntary muscle control.…”

“…All four of the skeletal muscle relaxants used by patients in our study are classified as non-benzodiazepine antispasmodic agents, although Tizanidine can be categorized as an antispasticity agent as well. [22][23][24] Cyclobenzaprine is thought to act at the level of the brainstem, 25 and has also been proposed to act as a 5-HT 2 receptor antagonist in the spinal cord. 26 While the exact mechanism of action of Metaxalone and Methacarbamol remains unknown, both are similarly thought to act as general CNS depressants with resulting depression of motor neuron activity, without a direct effect on skeletal muscle.…”

Skeletal Muscle Relaxants

“…[1][2][3] In animal studies, these agents exert their muscle-relaxing effects by inhibiting interneuronal activity and blocking polysynaptic neurons in the spinal cord and descending reticular formation in the brain. The exact mechanism of action for these various agents has not been fully elucidated.…”

“…2 Baclofen is unique in that it can be administered intrathecally in cases of severe spasticity and for patients who do not tolerate or have failed oral therapy. This drug is mainly used for spasticity associated with CNS disorders (multiple sclerosis [MS], spinal cord lesions).…”