0793 Nearly 25% of Restless Legs Syndrome (RLS) Patients Nationally Treated with Dopamine Agonists are Taking Higher Doses than the Maximum Recommended by FDA and Expert Guidelines

Introduction Dopamine agonists (DAs) have been first-line therapy for restless legs syndrome (RLS) for 30 years. Long-term DA use is associated with augmentation, a dose-related iatrogenic worsening of RLS, which results in a vicious cycle of escalating DA dosing to manage worsening symptoms. The objective of this study was to investigate rates of high-dose DA prescribing in patients with RLS nationally. Methods Patients with a diagnosis of RLS (ICD-10 G255.81), and no diagnosis of Parkinson’s disease, treated with rotigotine, pramipexole, and ropinirole, alone or in combination for >180 days, were identified from National Prescription Audit database from October 2017-September 2018. Daily total dosage was grouped into low (FDA-approved) and high (above FDA-approved) dose ranges, respectively (rotigotine: >0-≤3mg/>3mg; pramipexole: >0-≤0.75mg/>0.75mg; ropinirole: >0-≤4mg/>4mg). When DAs were used in combination with each other, dose-equivalent algorithms were used (rotigotine/ropinirole/pramipexole, 1:1:4). Results Prescriptions for 244,423 patients meeting inclusion criteria were sampled, constituting 71,181,466 therapy days. For all patients on DA therapy for RLS, 23.5% (57,552/244,423) were prescribed higher than FDA-recommended doses. For patients on DA monotherapy, high-dose prescriptions were provided to 42.7% (819/1919) on rotigotine, 40.7% (38,342/94,275) on pramipexole, and 11.5% (16,900/146,355) on ropinirole. Nearly one-quarter (23.2%) of all pramipexole monotherapy prescriptions were for very high dosages (>1.25 mg). For patients on DA combination therapy, high-dose prescriptions were provided to 79.6% (1,491/1,874). Conclusion Roughly 25% of RLS patients treated with DAs were prescribed doses above FDA and expert guideline-recommended maximum doses. Patients on DA combination therapy had substantially higher rates of cumulative high-dose prescriptions. High-dosage DA use is likely due to dose escalation in response to augmentation, risking further augmentation and adverse events such as impulse control disorders. Prescriber education on risks of high-dose DA prescribing for RLS is important. Support Arbor Pharmaceuticals, LLC