[Drug-induced Parkinsonism as Viewed from Neurologist]

Drug-induced Parkinsonism (DIP) is a common iatrogenic movement disorder. Its clinical manifestations cannot be distinguished from those of idiopathic Parkinson's disease. Prior exposure to dopamine receptor-blocking agents (DRBA) is required for diagnosis. This article reviews the epidemiology, pathophysiology, clinical features, ancillary testing, and treatment of DIP. Clinicians must always suspect DIP when a patient develops subacute Parkinsonism while taking DRBA. Ancillary testing such as DaT scans is often helpful in identifying prodromal Parkinson's disease. When DIP develops, steps should be taken to discontinue the offending agent or, in the case of antipsychotics, dose reduction or a change to an agent with a lower risk of DIP. L-dopa may be required to control parkinsonism in patients with DIP and prodromal PD.