Which medication is least likely to cause drug-induced Parkinsonism?

Citalopram is a selective serotonin reuptake inhibitor (SSRI) primarily used as an antidepressant. It works by increasing the levels of serotonin in the brain, which can improve mood and alleviate symptoms of depression and anxiety. Unlike the other medications listed, citalopram does not have significant dopaminergic antagonistic properties.

Drug-induced Parkinsonism is often a result of medications that block dopamine receptors, particularly typical antipsychotics like haloperidol and certain atypical antipsychotics like olanzapine, as well as prokinetic agents like metoclopramide that also affect dopamine pathways. Since citalopram does not interact with dopamine receptors in the same way, it is least likely to induce symptoms similar to Parkinson's disease, such as tremors, rigidity, and bradykinesia, making it the correct choice for this question.

Understanding the pharmacological profiles of these medications can help clarify why certain drugs are associated with drug-induced movement disorders while others are not.