Final answer:
Antiarrhythmic agents prolong the QT interval when interacting with antipsychotics.
Step-by-step explanation:
Drug that interact with antipsychotics by prolonging the QT interval fall into the category of antiarrhythmic agents. These drugs are used to treat irregular heart rhythms (arrhythmias) and can have an impact on the QT interval, which is a measure of the electrical activity of the heart.