Delayed ON is one of the motor complications of advanced PD patients that effect of anti-parkinsonian medication is delayed more than 40 minutes after intake. In the most severe cases, the effect does not appear even until next medication schedule, so called No ON status. It is important to manage delayed ON properly because it can interfere motor functions and quality of life of PD patients.~Levodopa/benserazide dispersible can be absorbed rapidly in the intestine, so theoretically it can break the poor response to conventional treatment of PD patients with delayed ON. However, this has not been proven by clinical trials till now.
The purpose of this study is to determine whether levodopa/benserazide dispersible is effective in the adjunctive treatment of Parkinson's disease (PD) patients with delayed ON.