Antiparkinson drugs are medicines that relieve the symptoms of Parkinson's disease and other forms of parkinsonism.

Parkinsonism is a group of disorders that share four main symptoms: tremor or trembling in the hands, arms, legs, jaw, and face; stiffness or rigidity of the arms, legs, and trunk; slowness of movement (bradykinesia); and poor balance and coordination. Parkinson's disease is the most common form of parkinsonism.

All types of parkinsonism occur when nerve cells in a particular part of the brain die or lose the ability to function. These cells normally produce a chemical called dopamine, that helps relay signals to different parts of the brain. This process is important in producing smooth, coordinated movement throughout the body. When dopamine-producing cells are lost, normal movement becomes impossible. In people with late-stage Parkinson's disease, 80% or more of these important cells are dead or impaired.

There is no cure...