Drug Insight: new drugs in development for Parkinson's disease.

For many years, levodopa has given most patients with Parkinson's disease excellent symptomatic benefit. This agent does not slow down the progression of the disease, however, and it can induce motor fluctuations and dyskinesias in the long term. The other available antiparkinsonian agents also have drawbacks, and as a consequence research into antiparkinsonian drugs is expected to take new and different directions in the coming years.