[Drug therapy of patients with early-stage parkinson's disease].

A guideline regarding the initial therapy for parkinsonian patients is described in this article. The basis for the selection of levodopa or a dopamine(DA) agonist for the initial therapy should depend on the patients' clinical characteristics. Young age, less severe condition of the disease, and absence of dementia are the most important determining factors to initiate DA agonist therapy. In this therapy, the dose should be based on the standard dose of the drug, which is obtained by previous clinical trials. In the case that the initial DA agonist therapy failed, or in the case that levodopa was initially used, the combined use of a DA agonist and levodopa should follow in the earlier period of the therapy.