Selegiline in the early and late phases of Parkinson's disease.

Selegiline is a useful adjuvant drug in the treatment of Parkinson's disease. In the early phase selegiline can be given in monotherapy. Its effect is not always sufficient to eliminate all the symptoms. In spite of this observation the administering of selegiline as monotherapy can be useful because in case of the immediate introduction of levodopa therapy untoward effects may appear in an early stage of treatment. In the course of substitution therapy selegiline successfully replaces about 30% of levodopa administered in "de novo" parkinsonian patients. Selegiline has a favourable beneficial effect in reducing the mild forms of response fluctuations. The addition of selegiline in such patients to the continuing substitution therapy prevents the development of more severe "on-off" manifestations. In severely disabled patients with irregular response swings or permanent akinesia the use of selegiline as an adjuvant drug cannot modify anymore the course of the disease.