Low-dose levodopa therapy in Japanese patients with Parkinson's disease: a retrospective study

To investigate the efficacy and the rate of adverse events of chronic low-dose levodopa-carbidopa therapy in Japanese patients with Parkinson's disease (PD).

A total of 92 Japanese PD patients treated with low doses of levodopa from the outset were studied. Both disease-specific motor disabilities and quality of life (QOL) in the patients were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS) and the Parkinson's Disease 39 Quality of Life Questionnaire (PDQ39), respectively.

In the overall patient group, the mean duration of treatment, the mean daily dose of levodopa, the disability scores and the motor scores of UPDRS were 6.2 years, 186.4 mg, 8.0 and 19.2, respectively. The rates of motor fluctuations, dyskinesias and hallucinations were 8.7%, 6.5% and 14.1%, respectively. The mean summary index of PDQ39 scores was 23.1. Patients with motor fluctuations showed a significantly earlier disease onset. Dose of levodopa, age at onset, and treatment duration were not associated with the occurrence of dyskinesias. Patients with hallucination had higher doses of levodopa and dopamine agonist.

Our results demonstrate that chronic administration of a low-dose levodopa preparation can provide satisfactory benefit with a low incidence of motor complications, and can result in good QOL in Japanese patients with PD. The concomitant use of a small amount of dopamine agonist and amantadine from the outset has partly contributed to a reduced dose of levodopa and the lesser occurrence of motor complications.