[QTc prolongation induced by intravenous sedation with Haloperidol, Prothipendyl and Lorazepam]

Specific sedation of acute psychotic patients with iv Haloperidol has been repeatedly criticized due to its cardiac risk on the basis of QTc prolongation, cumulating in the fact that iv application is no longer recommended according to the producer. Since Haloperidol still provides the only iv formulation of a high potency neuroleptic medication, and iv application offers some crucial advantages over other forms of application, we wanted to objectify QTc prolongation of Haloperidol iv as well as QTc prolongation of Prothipendyl iv, a low potency neuroleptic medication for unspecific sedation.

In our department all treatments with Haloperidol and Prothipendyl iv are ECG monitored and documented following an appointed guideline. Over 3 years all treatments according to this scheme and additionally treatments with Lorazepam iv have been analyzed regarding QTc prolongation. Non-parametric tests have been applied due to missing normal distribution of the data.

99 patients have been included in the survey. According to the iv medication applied patients have been divided into different subgroups. A significant QTc prolongation compared to the Lorazepam control group could be seen in the Haloperidol/Prothipendyl combination group as well as in the Prothipendyl monotherapy group, but not in the haloperidol monotherapy group. When patients were included, who additionally had received Lorazepam, results did not differ essentially with the exception that the Haloperidol/Prothipendyl combination had a significant greater prolongation than the Haloperidol group.

Our data proves the well known fact that Haloperidol iv causes a pronounced QTc prolongation. However QTc prolongation by iv Prothipendyl is still more pronounced according to our data. Most potent in producing a QTc prolongation proved a combination of Prothipendyl and Haloperidol, a fact that most likely depicts a dose effect. Since we assume, that there will be continuing need for iv medication with Haloperidol and Prothipendyl in the future, due to lack of arguable alternatives, we recommend safety measures like ECG monitoring not only for Haloperidol, but too for unspecific sedation with iv Prothipendyl.