title: Adenosine A2A receptor antagonist istradefylline 20 versus 40 mg/day as augmentation for Parkinson's disease: a meta-analysis.
abstract: BACKGROUND
  Adenosine A2A receptor antagonist istradefylline 20 mg/day has been approved this year for manufacturing and market in Japan. Therefore, we did this meta-analysis to systematically evaluate the clinical applicability of 40 mg/day as augmentation to levodopa in patients with Parkinson's disease (PD).
  
  
  METHODS
  Randomized controlled trials (RCT) that compared istradefylline with placebo for short-course treatment of PD in adults were systematically reviewed up to November 2013. Outcome measurements were daily off time and unified Parkinson's disease rating scale (UPDRS) Part III score (on state). Random-effect model was used.
  
  
  RESULTS
  Data were obtained from four RCTs. In these RCTs, 405 patients received istradefylline 20 mg/day and 420 patients received 40 mg/day. The pooled weighted mean difference was 0.17 with 95% confidence interval (CI)  =  [-0.23, 0.56] on daily off time and 0.70 with 95% CI  =  [-0.89, 2.29] on UPDRS Part III score (on state). The adverse events analysis showed that 20 and 40 mg/day had comparable acceptability. Heterogeneity was not existed.
  
  
  CONCLUSIONS
  These results indicate that istradefylline 40 mg/day as augmentation shows potential promise on clinical applicability, and is worthy of further study. Limited by the number of included RCTs, future studies are needed to verify and support this conclusion, and assess the long-term effect of istradefylline, the effect of istradefylline as monotherapy and other dose of istradefylline.
authors.forename: Chuan
authors.initials: C
authors.lastname: Zhu
authors.forename: Guowei
authors.initials: G
authors.lastname: Wang
authors.forename: Jinqing
authors.initials: J
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Chaoli
authors.initials: C
authors.lastname: Wang
authors.forename: Yajie
authors.initials: Y
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Lin
authors.forename: Hong
authors.initials: H
authors.lastname: Ran
mesh_terms: D058917:Adenosine A2 Receptor Antagonists / Q000008:administration & dosage* / Q000627:therapeutic use*; D000368:Aged; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy*; D011687:Purines / Q000008:administration & dosage* / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D011687:Purines; C111599:istradefylline; D007980:Levodopa
keywords: Istradefylline; PD,; Parkinson's disease,