Istradefylline: a novel drug for ‘off’ episodes in Parkinson’s disease

Istradefylline, a selective adenosine A_2A receptor antagonist, has recently been approved for the treatment of ‘off’ episodes in patients with Parkinson’s disease (PD) who are already receiving treatment with levodopa/carbidopa. The aim of the article is to review the efficacy, safety and tolerability of istradefylline in the management of ‘off’ episodes of PD, based on English language articles on this topic indexed in PubMed or in the National Institute of Health clinical trials registry during 2003–2019. Based on the beneficial outcomes of phase 2 or 3 clinical trials and a post-marketing surveillance study in Japan, istradefylline is a promising option for treating ‘off’ episodes in PD patients already receiving levodopa/carbidopa. The important adverse effects observed in the clinical trials were dyskinesia and hallucination. Head-to-head clinical trials are required to compare the efficacy of istradefylline with other classes of drugs, so as to ascertain its relative efficacy in managing the ‘off’ phase of PD.