Replacing a dopamine agonist by the COMT-inhibitor tolcapone as an adjunct to L-dopa in the treatment of Parkinson's disease: a randomized, multicenter, open-label, parallel-group study.

Objective: This study investigated the feasibility, safety, and potential benefit in motor symptom control when switching from a dopamine agonist to tolcapone as an adjunctive therapy in patients with Parkinson's disease with a fluctuating response to levodopa (l-dopa). We determined the efficacy of 2 replacement strategies.

Methods: In this 10-week, randomized, open-label, stratified, parallel-group trial, 150 patients on a stable regimen of l-dopa/decarboxylase inhibitor in combination with bromocriptine, lisuride, or pergolide were switched to tolcapone.