Skeletal muscle relaxants
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.