Response variations in the treatment of Parkinson's disease

The problems of long-term levodopa therapy tend to occur earlier if levodopa is combined from the start with a decarboxylase inhibitor. We conducted a retrospective study of 123 patients. Among patients treated with levodopa without a decarboxylase inhibitor, only 25% had response variations (end-of-dose deterioration, on-off response fluctuation) after 6 years of treatment. Among patients treated with both levodopa and a decarboxylase inhibitor, 90% showed response variations after 6 years of therapy.