Levodopa gets converted to dopamine in the brain and replaces what's missing. Medications that chemically look like dopamine can be used alone or in combination with Sinemet to control symptoms. The agonists last for a longer time in the brain than Sinemet does, thus providing smoother control of symptoms. The newest class of medications inhibit enzymes that break down dopamine. Use of these enzyme inhibitors makes the effect of Sinemet last longer.
Medications help to control the tremors, stiffness, slowness and walking difficulties.
For some people, medications get rid of their symptoms completely, while for others, symptoms are lessened but still present. Medication is effective to some degree for the majority of people with Parkinson's disease. These Parkinson's-plus syndromes do not respond well to medications, and many people feel better without medication. There is an amazing amount of research being done on Parkinson's disease. Scientists are focusing on the cause of cell death and studying how genes cause the disease.