Apomorphine and levodopa infusion for motor fluctuations and dyskinesia in advanced Parkinson disease.

ABSTRACT

Development of motor fluctuations and dyskinesia characterizes the transition from early to advanced Parkinson disease stage. Current therapeutic strategies to manage motor complications aim at increasing the number of levodopa administrations and extending its benefit by the association of enzyme blockers and dopamine agonists. However, as disease progresses, mobility becomes progressively dependent on levodopa absorption and its plasma bioavailability, resulting in loss of independence, worse quality of life and increased caregiver burden. If patients continue to experience off-time with functional impact on activities of daily living after best medication adjustments, implementation of infusion with apomorphine or levodopa, and surgical therapies should be considered. Presence of troublesome dyskinesia would also favor the choice of an advanced treatment. Compared with pulsatile oral therapy, both apomorphine and levodopa infusion determine more continuous striatal dopamine receptors stimulation than oral levodopa resulting in significant reduction of off-time and dyskinesia, particularly peak-dose, although not in their complete resolution. This observation proves that abnormal synaptic plasticity and connectivity changes cannot be reversed once they are established. Early implementation of these therapeutic strategies ideally would target patients as soon as motor complications begin rather than at late stage of advanced Parkinson's disease (PD) before dyskinesia have manifested. Preliminary evidence from early deep brain stimulation in patients with short disease duration and modest motor complications suggests that this approach can positively impact quality of life. It is conceivable that changing our PD treatment algorithm and implementing device-aided therapies at the beginning of the advanced phase before dyskinesia has established, will provide more stable motor conditions and longer functional autonomy.