In recent years, a few of randomized controlled trials (RCTs) about
amantadine for treating
dyskinesia in
Parkinson's disease (PD) were completed. Here, we conducted a systematic literature review about the clinical research to provide the updated evidence for treating
dyskinesia. Electronic search of Medline, PubMed, Cochrane Library, and other databases up to May 2016 for relevant studies was performed. We selected the Unified Parkinson's Disease Rating Scale IV (UPDRS IV) and
Dyskinesia Rating Scales (DRS) as efficacy outcomes of
amantadine on
dyskinesia. Pooled data from included studies was then used to carry out meta-analysis. A total of eleven eligible RCTs that involved 356 PD patients with existing
dyskinesia were included in the present study. The results of meta-analysis showed that
amantadine significantly improved UPDRS IV (P < 0.0001) and DRS (P < 0.00001). Meanwhile, there was a mild reduction in Unified Parkinson's Disease Rating Scale III after
amantadine treatment in advanced PD patients with
dyskinesia (P = 0.01) compared with placebo. High dosage of
amantadine obviously improved existing
dyskinesia in PD, yet at the expense of the increased adverse events. It was necessary to detect the optimal therapeutic efficacy to balance the incidence of adverse events when we used
amantadine to treat existing
dyskinesia in PD patients.