Intravenous Haloperidol, Agitation, and the QTc: Misconceptions and Heuristics

Clinicians are commonly asked to make complex and potentially risky decisions in the face of uncertainty and incomplete information. Physicians frequently employ heuristics, or mental shortcuts, to convert challenging clinical questions into much simpler ones. Psychiatrists often encounter such challenges when asked to comment on the safety of intravenous haloperidol (IVH), particularly regarding risks of prolonging the corrected QT interval (QTc) or developing Torsades de Pointes (TdP). In light of the 2007 Food and Drug Administration warning about the risk of developing TdP with IVH, some providers, and even some institutions, have used QTc cut-off values to indicate when one can and cannot use IVH safely for managing acute agitation. In this perspective, we argue that (1) this practice represents an inappropriate use of a heuristic rather than a necessary risk-benefit calculation, and (2) that our updated understanding of the complex relationships among IVH, QTc, and TdP does not support the use of QTc cut-off values. We address some common misconceptions about the associations among IVH, QTc, and TdP, and discuss how reframing the decision-making process related to this dilemma may improve clinical care.