American Board of Internal Medicine (ABIM) Certification Practice Exam

Which two antipsychotics are the least likely to cause tardive dyskinesia?

1. Olanzapine and Risperidone

2. Quetiapine and Clozapine

3. Aripiprazole and Haloperidol

4. Fluphenazine and Lurasidone

The correct answer is: Quetiapine and Clozapine

The most reliable antipsychotics for minimizing the risk of tardive dyskinesia are quetiapine and clozapine. Tardive dyskinesia is a serious movement disorder often associated with the use of conventional (first-generation) antipsychotics, which tend to block dopamine receptors extensively. Quetiapine, an atypical antipsychotic, has a lower affinity for dopamine D2 receptors compared to many of its counterparts, leading to a lower incidence of extrapyramidal symptoms, including tardive dyskinesia. Similarly, clozapine is associated with a lower risk of these side effects, making it a preferred option for treatment-resistant cases and in individuals who are sensitive to extrapyramidal symptoms. This understanding is crucial because patients treated with first-generation antipsychotics, such as haloperidol or fluphenazine, have a higher risk of developing tardive dyskinesia due to their greater potency in dopamine receptor antagonism. Other atypical antipsychotics, like olanzapine and risperidone, still carry some risk, though they are generally lower than that of first-generation agents. Therefore, the unique pharmacological profiles of quetiapine