Spasticity is characterized by tightness or stiffness of the muscles and an inability to control these muscles. It most commonly occurs as a symptom of a central nervous system disorder or neuromuscular disorder. Spasticity is caused by an imbalance in the signals sent from the central nervous system to the muscles.

The most common conditions causing spasticity are cerebral palsy, brain injury, stroke, multiple sclerosis and injuries to the spinal cord. Symptoms include increased muscle tone, involuntary movements, overactive reflexes, pain, bone and joint deformities, permanent contraction of muscles and tendons (contractures), and a decrease in functional abilities.

Spasticity may be treated with occupational or physical therapy and medication. Drug classes used to treat spasticity are peripherally acting muscle relaxants, centrally acting muscle relaxants, anxiolytics, benzodiazepines and muscle relaxants and other neuromuscular blockers.