A 2018 Springer article examines drug repurposing in PD due to the ever-increasing costs and lengthy processes for drug development. Existing compounds are being approved for other indications as novel treatments in PD. Advances in rational and systemic drug repurposing have identified a number of drugs with potential benefits for PD pathology and offer a potentially quicker route to drug discovery. Among the drugs being considered for repurposing for PD are ambroxol; isradipine; Inosine; ursodeoxycholic acid; deferiprone; exenatide; Nilotinib and Simvastatin. Despite the potential advantages offered by drug repurposing, as a strategy, it offers unique challenges, including the unavoidable need for expensive and risky clinical trials to demonstrate safety and efficacy in a new population while the limited patent protection often means a lack of commercial interest or incentive for further investment.