Drugs that Cause Movement Disorders
Most of us learned in our professional training that neuroleptic agents cause movement disorders, or extrapyramidal symptoms (EPS).1 Neuroleptics, the older class of antipsychotic agents, which includes dopamine receptor blocking agents (DRBA), can cause tardive dyskinesia (TD), dystonia, akathisia, and Parkinsonism.
We also learned that newer antipsychotic agents, the so-called second-generation antipsychotics, do not cause EPS. However, dose-related EPS has been associated with olanzapine and risperidone use (> 6 mg/day doses), and there have been two reported cases of aripiprazole-induced EPS.2,3
So which symptoms indicate a drug-induced movement disorder (DIMD)? Patients with DIMDs have difficulty with social functioning, motor-task performance, interpersonal communication, and activities of daily living. They also are less likely to adhere to a medication regimen, making disease relapse and rehospitalization more likely.
Some DIMDs are worse than others. Neuroleptic-induced TD, for example, is in some cases irreversible and can lead to functional impairment so severe a patient cannot feed himself, speak clearly, or breathe easily. In addition, removal of the offending agent does not always resolve TD.4
Milder forms of neuroleptic-induced TD occur in about 20% of patients. In higher risk groups, such as older patients, milder forms of neuroleptic-induced TD may exceed 50%.
DIMDs often elude diagnosis by clinicians, partially because they look like other medical conditions such as restless legs syndrome, agitation, or drug withdrawal. Clinicians who understand the most likely DIMD culprits and the effect of each can better manage their patients. It’s also crucial for clinicians to pay attention to
