Because Selegiline potentiates the effects of levodopa the side effects of levodopa might be emphasised, particularly when the patient is on a very high dosage of levodopa. The addition of SELEGOS to maximal doses of levodopa may cause involuntary movement and/or agitation. Such side effects disappear when the levodopa dosage is decreased. Levodopa treatment can be reduced by an average of 30 percent when SELEGOS is added to the treatment. When an optimal levodopa dose has been established, the side effects of the combination have been found to be fewer than for levodopa alone.