Droperidol

WARNINGS Droperidol should be administered with extreme caution in the presence of risk factors for development of prolonged QT syndrome, such as: 1) clinically significant bradycardia (less than 50 bpm), 2) any clinically significant cardiac disease, 3) treatment with Class I and Class III antiarrhythmics, 4) treatment with monoamine oxidase inhibitors (MAOI's), 5) concomitant treatment with other drug products known to prolong the QT interval (see PRECAUTIONS, Drug Interactions ), and 6) electrolyte imbalance, in particular hypokalemia and hypomagnesemia, or concomitant treatment with drugs (e.g., diuretics) that may cause electrolyte imbalance. Effects on Cardiac Conduction: A dose-dependent prolongation of the QT interval was observed within 10 minutes of droperidol administration in a study of 40 patients without known cardiac disease who underwent extracranial head and neck surgery. Significant QT prolongation was observed at all three dose levels evaluated, with 0.1, 0.175, and 0.25 mg/kg associated with prolongation of median QTc by 37,44, and 59 msec, respectively. Cases of QT prolongation and serious arrhythmias (e.g., torsade de pointes, ventricular arrhythmias, cardiac arrest, and death) have been observed during post-marketing treatment with droperidol. Some cases have occurred in patients with no known risk factors and at doses at or below recommended doses. There has been at least one case of nonfatal torsade de pointes confirmed by rechallenge. Based on these reports, all patients should undergo a 12-lead ECG prior to administration of droperidol to determine if a prolonged QT interval (i.e., QTc greater than 440 msec for males or 450 msec for females) is present. If there is a prolonged QT interval, droperidol should NOT be administered. For patients in whom the potential benefit of droperidol treatment is felt to outweigh the risks of potentially serious arrhythmias, ECG monitoring should be performed prior to treatment and continued for 2-3 hours after completing treatment to monitor for arrhythmias. FLUIDS AND OTHER COUNTERMEASURES TO MANAGE HYPOTENSION SHOULD BE READILY AVAILABLE. As with other CNS depressant drugs, patients who have received droperidol should have appropriate surveillance. It is recommended that opioids, when required, initially be used in reduced doses. As with other neuroleptic agents, very rare reports of neuroleptic malignant syndrome (altered consciousness, muscle rigidity and autonomic instability) have occurred in patients who have received droperidol. Since it may be difficult to distinguish neuroleptic malignant syndrome from malignant hyperpyrexia in the perioperative period, prompt treatment with dantrolene should be considered if increases in temperature, heart rate or carbon dioxide production occur.