What unique side effect is associated with thioridazine?

Thioridazine is a typical antipsychotic that is particularly noted for its unique side effect of causing torsades de pointes, which is a type of polymorphic ventricular tachycardia that can lead to sudden cardiac arrest. This side effect is primarily related to thioridazine's potential to prolong the QT interval on an electrocardiogram due to its effects on cardiac repolarization. The risk of torsades de pointes is significant enough that thioridazine is typically reserved for cases where other treatments have failed, and it is important to monitor cardiac function closely in patients taking this medication.

Neuroleptic malignant syndrome is a serious but less specific complication associated with many antipsychotics, not uniquely tied to thioridazine. Agranulocytosis is a dangerous reduction in white blood cells that is more commonly associated with clozapine, another antipsychotic, rather than thioridazine. Finally, seizures can occur as a side effect of various antipsychotic drugs but are not a hallmark of thioridazine specifically. Therefore, the unique risk of torsades de pointes underscored thioridazine's distinct place in the spectrum of antipsychotic medications.