Levodopa use in Australia: an analysis of Pharmaceutical Benefits Scheme 10% data.

Background: Levodopa remains the mainstay of treatment of Parkinson's disease, however, over time motor fluctuations and levodopa-induced dyskinesia develop, requiring add-on therapies to control emerging symptoms. To date, however, there is no clear consensus in Australia, or elsewhere, at which dose of levodopa that add-on therapies should be considered. Objectives: The purpose of this study was to examine the treatment patterns of patients with Parkinson's disease in Australia, with particular focus on levodopa doses at the time of first add-on. Methods: This was a retrospective, observational, non-interventional study of patients with Parkinson's disease within the Australian Department of Human Services Pharmaceutical Benefits Scheme (PBS) 10% sample. Data on all reimbursed prescriptions (both general and concession), prescriber type and item code were extracted for patients who were dispensed at least three PBS reimbursed prescriptions for levodopa in the previous 12 months prescription from 1 January 2007 to 31 December 2021. Results: 154 850 unique patients were included, of whom 42 330 (27%) commenced add-on therapy during the period. In the 12 months prior to add-on therapy, levodopa doses ranged from 100 mg/day to 1000 mg/day. The majority of patients were prescribed add-on therapy by a neurologist and approximately 40% of patients were prescribed levodopa doses of 600 mg/day or more prior to the first add-on therapy being initiated. Conclusions: A large proportion of patients in Australia are managed with levodopa monotherapy doses that are considered high and many of these patients may benefit from the addition of add-on therapy to their regimen.