Background: Chronic levodopa treatment in Parkinson's disease (PD) may promote undesirable motor and non-motor fluctuations. Compared to chronic oral levodopa treatment, continuous infusion of levodopa/carbidopa intestinal gel (LCIG) in advanced PD reduces motor fluctuations. However, differences in their effect on acute non-motor changes were not formally demonstrated.
Objective: We performed a randomized, double-blind, double-dummy, crossover study to compare acute non-motor changes between intermittent oral immediate-release carbidopa/levodopa (LC-IR) and LCIG.
Methods: After > 12-h OFF, thirteen PD patients chronically treated with LCIG and without history of non-motor swings, were allocated to receive first, LCIG infusion plus three oral doses of placebo, or placebo infusion plus three oral doses of LC-IR. Over-encapsulated oral medication (LC-IR or placebo) was administered every 2 h. We monitored plasmatic levels of levodopa, motor status (UPDRS-III), mood, anxiety, and frontal functions at baseline (0-h) and hourly after each oral challenge.
Results: Repeated-measures ANOVAs showed significant group by treatment interaction indicating more fluctuations of levodopa plasma levels with LC-IR. No significant interactions were seen in the temporal profile of motor status, anxiety, mood and cognition. However, point-to-point parametric and nonparametric tests showed a significant more marked and more sustained improvement in anxiety scores under LCIG. A significant improvement of mood and verbal fluency was seen a + 3-h only under LCIG.
Discussion: Our sample of advanced PD patients exhibited moderate but significant non-motor fluctuations. LCIG was associated with a more favorable profile of acute affective and cognitive fluctuations that was particularly expressed at the first part of the infusion curve.
Keywords: Anxiety; Executive function; Levodopa/carbidopa intestinal gel; Mood; Non-motor fluctuations; Parkinson’s disease; Pharmacokinetics.