Movement disorders (MD) encountered in the emergency department (ED) range from the familiar Parkinsonism and drug-induced dystonias to rare disabling hemiballism secondary to a stroke. Movement disorders can be classified into four broad categories based on phenomenological features, clinical pharmacology, and neuropathology. It includes hypokinetic disorders identical to Parkinsonism's syndrome, hyperkinetic/choreic movement disorders, tremors, and myoclonus. The cause-and-effect relationship between the drug and the movement disorder is poorly understood, but preexisting central nervous system (CNS) pathology likely predisposes to the development of movement disorders. Commonly prescribed medications that result in movement disorders include antiepileptics, neuroleptics, stimulants, oral contraceptives, antihistaminics and anticholinergics, and antidepressants. The use of monoamine oxidase (MAO) inhibitors is associated with tremors and less often with myoclonic jerks. Tricyclic antidepressants such as amitriptyline, imipramine, and nortriptyline cause choreiform movements infrequently, particularly orofacial dyskinesia.