Medical Pharmacology Chapter 20:  Neuromuscular Blocking Agents

Neuromuscular Blocking Drugs:  Skeletal Muscle Relaxants

• Spasticity characteristics

  • Increased in tonic stretch reflexes

  • Increased flexor muscle spasm

  • Muscle weakness

• Clinical conditions associated with spasticity

  • Cerebral palsy

  • Multiple sclerosis

  • Stroke

• Mechanisms of clinical spasticity

  • Reflex arc involvement

  • Higher center involvement ("upper motor neuron disease") affects descending pathways leading to alpha-motoneuron hyperexcitability

• Mechanisms of drug action that diminish spasticity

  • Alteration in stretch reflex arc

  • Attenuation of excitation-contraction coupling