Retrospective review across six EDs found only 32.3% of Parkinson's patient encounters received their home carbidopa-levodopa in the ED and fewer than 10% received it within defined timeliness standards, with mean time to administration ~6 hours.

Clinically important identification of a widespread, actionable care-delivery failure that increases risk of iatrogenic deterioration in PD patients and supports targeted operational interventions (protocols, EHR alerts, staff training) rather than novel molecular therapeutic discovery.

INTRODUCTION: Patients with Parkinson's disease (PD) frequently present to the Emergency Department (ED). Whether for PD-related complications or unrelated concerns, maintaining their antiparkinsonian medication regimen without interruption is crucial. Delays or omissions can lead to significant morbidity and mortality. Despite this, the importance of timely ordering and administration of antiparkinsonian medications is often underrecognized in the ED. METHODS: We performed a retrospective chart review across a single health system comprising one academic and five community EDs, three of which are critical access hospitals. Adults aged ≥ 65 years with an active outpatient carbidopa-levodopa (C-L) prescription presenting between September 1, 2024, and August 31, 2025, were included. The primary outcome was the proportion of patients who received their prescribed C-L during the ED encounter. Timeliness was assessed using two definitions: a primary, idealized standard of administration within 30 min of the scheduled dose, and a secondary, system-based standard of administration within a two-hour window. RESULTS: A total of 282 patient encounters involving 87 unique patients were included (mean age 80.1 years; 61.7% male; 99.3% White). Mean ED length of stay (LOS) was 8 h and 53 min. C-L was administered in only 91 encounters (32.3%). Among the 282 ED encounters, 12 (4.3%) met the idealized timeliness definition for C-L administration, and 18 (6.4%) met the system-defined standard. Among the 91 encounters with a C-L order, 13.2% met the ideal definition and 19.8% met the system standard. Mean time from ED arrival to medication administration was 6 h 11 min. Most administrations occurred 1-4 h (39.6%) or 4-8 h (26.4%) after the scheduled dose. CONCLUSION: Less than one-third of older adults with PD received their home antiparkinsonian medication in the ED, and fewer than 10% received it on time. Targeted interventions to ensure timely medication administration are needed to prevent iatrogenic harm in this vulnerable population.