Tardive Dyskinesia Associated with Switching to Clozapine: A Case Report

Chung, Yong Chul; Lee, Chun Rong; Hyun, Ung

Abstract

OBJECTIVE
Clozapine is known as an atypical antipsychotic drug which has less side effects in the extrapyramidal system than typical antipsychotic drugs and recommended as a treatment of choice in severe tardive dyskinesia (TD). However, it has been reported that the existing TD was worsened or new TD appeared in some cases where the antipsychotic drugs were switched to clozapine.
METHODS
We experienced a single case in which TD was appeared in the tongue and jaw 5 months after chlorpromazine was switched to clozapine.
RESULTS
The subject was 57 years old male patient with bipolar disorder. He had been treated intermittently with lithium and chlorpromazine for over 30 years. Five months after switching from chlorpromazine to clozapine, TD appeared in the tongue and jaw. Using Extrapyramidal Symptom Rating Scale (ESRS), the dyskinesia score was 10. Hence, clozapine was stopped and chlorpromazine was re-administrated resulting gradual improvement of TD. The dyskinesia score of ESRS was dropped to 6.
CONCLUSION
It is speculated that this case is most likely a withdrawal tardive dyskinesia but other possibilities should be considered too. The question "Does withdrawal tardive dyskinesia occur more easily when switched to clozapine which has a weak dopamine antagonism?" should be addressed in future study.