Trihexyphenidyl triggered hypomania in a bipolar patient

Abstract

We observed a case of tardive dyskinesia after regular use of low dose chlorpromazine. An anticholinergic agent; trihexyphenidyl (THX) was used to treat the tardive dyskinesia. Treatment response was satisfactory, but brief hypomanic episodes occured. Because the patient was symptom free for long periods of time, we suspected that THX may have a negative effect on the course of the disease or it may have induced hypomania. These episodes were controled with short term use of olanzapine. When the dose of THX was further increased, we determined elevation of mood. History of bipolar disorder in his family and having the early onset type of bipolar disorder were features of our case making the tardive movement disorder more likely. Although THX may be an effective option in tardive dyskinesia, change in the course of the disease in bipolar patients may be a possibility.