Skeletal muscle relaxants
Skeletal muscle relaxants relieve musculoskeletal pain or spasmand severe musculoskeletal spasticity (stiff, awkward move-ments). Theyâ€™re used to treat acute, painful musculoskeletal con-ditions and the muscle spasticity associated with multiple sclero-sis (MS) (a progressive demyelination of the white matter of the brain and spinal cord that causes widespread neurologic dysfunc-tion), cerebral palsy (a motor function disorder caused by neuro-logic damage), stroke (reduced oxygen supply to the brain, result-ing in neurologic deficits), and spinal cord injuries that can result in paralysis or death.
Exposure to severe cold, lack of blood flow to a muscle, or overexertion can send sensory impulses from the posterior senso-ry nerve fibers to the spinal cord and the higher levels of the cen-tral nervous system (CNS). These sensory impulses can cause a reflex (involuntary) muscle contraction or spasm from trauma, epilepsy, hypocalcemia (low calcium levels), or muscle disorders.
The muscle contraction further stimulates the sensory receptors to a more intense contraction, establishing a cycle. Centrally act-ing muscle relaxants are believed to break this cycle by acting as CNS depressants.