Parkinson's disease is a progressive neurodegenerative disorder characterized by rest tremors, bradykinesia , rigidity , postural instability , gait dysfunction and several non motor symptoms . The marked difference in drug response and adverse effect profile among patients led to search of genetic markers and polymorphism associated with response to antiparkinsonian drugs which will enable us to predict an individuals  response to drugs in terms of both efficacy and toxicity. Hence efforts to define the role of genetic polymorphism in optimizing pharmacotherapy of Parkinson's disease have been undertaken and some promising genetic loci for the treatment have been determined. Therefore we aim to present a critical review of pharmacogenetic aspects of levodopa , dopamine agonists and COMT inhibitors and describe gene polymorphism of interest for future research.Â
