A Case of QT-interval Prolongation in the Context of High-dose, Intravenous Midazolam in a Methadone Maintained Patient

The following case illustrates a case of significant prolonged QT-interval (QTc) prolongation following intravenous administration of high-dose midazolam in a patient with severe hyperactive delirium. A prolonged QTc represents a potentially life-threatening condition associated with Torsades de Pointes (TdP) and sudden cardiac death (SCD). Although the predictive value of a prolonged QTc and the occurrence of TdP and SCD has not yet been fully established, heightened awareness in medicine and psychiatry has arisen with respect to the administration of psychotropics. Benzodiazepines, although known to prolong the QTc, have been considered as rather safe medications with this respect. For example, low-dose midazolam has not been shown to cause QTc prolongation. In the following case, however, high-dose midazolam caused a significant prolongation of the QTc, which has to date, not yet been reported.