Droperidol, when used for sedation during ERCP, may prolong the QT interval

Abstract

Droperidol is a known effective adjunctive agent for sedation/analgesia during endoscopic procedures, particularly in patients who are difficult to sedate with narcotics and benzodiazepines alone. However, the Food and Drug Administration (FDA) warning about potential droperidol-related fatal cardiac arrhythmias, issued in December 2001, led to concern about its safety in current clinical practice. In this study, we evaluated the effects of droperidol on the Bazett's corrected QT interval (QTcB) administered to patients undergoing ERCP and frequency of cardiac arrhythmias. We retrospectively reviewed the medical records of patients who, at our institute, underwent ERCP while under sedation/analgesia and who received droperidol. Our protocol for patients who are considered to be candidates for droperidol use includes obtaining an ECG before and 1 to 3 hours after the procedure. From April 2002 to October 2004, 6292 ERCPs were performed, of which 3113 patients with normal baseline QTcB (2001 women, 1112 men) received droperidol. Mean dosages were 4.3 mg (range, 1.25-10 mg) in women and 4.5 mg (range, 1.25-13.75 mg) in men. A total of 233 patients (7.48%; 133 women, 100 men) developed QTcB prolongation. Mean increases of the QTcB above the upper limit of normal were 16 milliseconds in women (range, 1-194 milliseconds) and 22 milliseconds in men (range, 1-310 milliseconds). Of these, 15 patients (0.48%; 8 women, 7 men) had marked prolongation of the QTcB (defined QTcB, >500 milliseconds). No serious dysrhythmias occurred. Droperidol at usual doses during sedation/analgesia may precipitate QTcB prolongation above the normal range. However, no QT-related arrhythmias were noted in this study. Clinically significant cardiac events are probably rare with droperidol, despite documented QTcB effects. Baseline electrocardiogram for excluding patients with prolonged baseline QTcB and 1 to 3 hours afterward monitoring appears adequate when using droperidol. The study is still too small to detect very infrequent arrhythmia events.