[Optimal dose of levodopa-carbidopa intestinal gel in the treatment of diphasic dyskinesia and freezing of gait].

A 58-year-old man who was diagnosed with Parkinson's disease (PD) at age 46 developed levodopa-induced motor complications seven years after diagnosis, along with dyskinesia. Treatment with levodopa-carbidopa intestinal gel (LCIG) was introduced at age 57. His dyskinesia and freezing of gait (FOG) worsened after the introduction of LCIG. Considering the pathophysiological mechanism of diphasic dyskinesia, the dose of levodopa was increased since it was considered necessary to exceed the upper threshold of diphasic dyskinesia. As a result, dyskinesia and FOG became severe and he was admitted to our hospital. After reducing the levodopa equivalent dose to control the dyskinesia to an almost negligible level, his FOG also improved and his activities of daily living improved markedly. This case highlights the difficulty in treating dyskinesia and FOG in advanced-stage PD patients with a narrow therapeutic window.