neurologic and neuromuscular disorders

Learning objectives In this chapter, you’ll learn: • classes of drugs used to treat neurologic and neuromuscular disorders uses and actions of these drugs • absorption, distribution, metabolism, and excretion of these drugs • drug interactions and adverse reactions to these drugs. The neurologic, or nervous, system includes the central nervous system (brain and spinal cord) and the peripheral nervous system (somatic and autonomic nervous systems). The neuromuscular system consists of the muscles of the body and the nerves that supply them. Several types of drugs are used to treat disorders of these two major systems, including: • skeletal muscle relaxants • neuromuscular blocking drugs • antiparkinsonian drugs • anticonvulsant drugs • antimigraine drugs. Skeletal muscle relaxants Skeletal muscle relaxants relieve musculoskeletal pain or spasms and severe musculoskeletal spasticity (stiff, awkward movements). They’re used to treat acute, painful musculoskeletal conditions and muscle spasticity associated with multiple sclerosis (MS), a progressive demyelination of the white matter of the brain and spinal cord that causes widespread neurologic dysfunction; cerebral palsy, a motor function disorder caused by neurologic damage; stroke, the death of brain cells caused by a reduced supply of oxygen to the brain, which can result in neurologic deficits; and spinal cord injuries, which can result in paralysis or death. This section discusses centrally acting, direct-acting, and other skeletal muscle relaxants. Centrally acting agents Centrally acting skeletal muscle relaxants are used to treat acute muscle spasms caused by such conditions as anxiety, inflammation, pain, and trauma. They also treat spasticity from such conditions as MS and cerebral palsy. Examples of these drugs include: • carisoprodol • chlorphenesin • chlorzoxazone • cyclobenzaprine • metaxalone • methocarbamol • orphenadrine • tizanidine