Droperidol與QT間期延長
靜脈注射droperidol曾有QT間期延長和嚴重心律失常(如尖端扭轉心律失常)的報道, 當中某些個案的病人死亡。加拿大衛生部(Health Canada)近日發出通告, 修改含droperidol注射液的說明書。綜合上述通告和文獻Micromedex後, 本處對droperidol注射液提供下列安全性的最新資訊：
1. 因可能引發嚴重或危及生命的心律失常, droperidol禁用於已知或懷疑QT間期延長(例如, 男性QTc間期大於440毫秒;女性QTc間期大於450毫秒)的病人, 包括先天性長QT綜合症(congenital long QT syndrome)的病人。
2. 所有病人於注射droperidol前, 須檢測心電圖(ECG), 以排除QT間期延長。該藥只能於醫院使用, 以便對病人進行持續的心電圖監測。監控應由治療開始時進行, 以及持續至完成治療後2至3小時。
3. 對於具有QT間期延長風險的病人, 如正在服用其他可引致QT間期延長的藥物﹑心動過緩﹑心臟病﹑65歲以上的長者﹑電解質不平衡以及併用可引致電解質不平衡的藥物時, 倘若需要使用droperidol, 醫生必須十分謹慎。
4. 如病人在施藥期間發生QT間期延長, 應停止注射以及採取適當的治療措施。
Tigecycline與死亡風險增加
一項對多個臨床試驗的綜合分析研究指出, 相對於其他用於治療嚴重感染的抗生素, 使用tigecycline的病人, 其死亡的風險可能更高。上述因果關係尚未確立, 而大部份的死亡個案皆與病人的感染惡化有關。然而, 大部份的死亡個案發生在該藥用於治療醫院獲得性肺炎, 特別在與插管相關的肺炎病人中, 而目前該藥的適應症為社區獲得性肺炎、複雜性皮膚或皮下組織感染以及複雜性腹腔感染。
本處現提醒衛生專業人士, 對醫院獲得性肺炎(包括與插管相關的肺炎)以及糖尿病腳部感染等嚴重感染的病人, 基於使用tigecycline可能增加死亡的風險, 因此, 醫生應選擇其他治療方案。
Droperidol and QT interval prolongation
It is known that cases of QT interval prolongation and severe arrhythmias (eg. torsades de pointes) plus the occurrences of some fatalities occurred in patients receiving intravenous droperidol. Health Canada recently announced revisions on the product information of droperidol injection. Upon cross-checking the above labelling updates with the current droperidol drug summary on Mircromedex, DFF acknowledged and would like to share the following safety recommendation on droperidol injections:
1. Droperidol is contraindicated in patients with known or suspected QT interval prolongation (i.e., QTc interval greater than 440 msec for males or 450 msec for females) including congenital long QT syndrome since serious or life-theatening arrhythmias may occur.
2. All patients should undergo an ECG screen prior to administration of droperidol to detect prolonged QT interval. Injectable droperidol should only be used in the hospital setting to allow for ECG monitoring, which should start with treatment and be continued for 2 to 3 hours after completing treatment.
3. Extreme caution is needed when using droperidol in patients with risk factors for QT prolongation such as concomittant use of other arrhythmogenic agents, bradycardia, cardiac disease, aged over 65, electrolyte imbalance or medications that may cause electrolyte imbalance.
4. If a prolonged QT interval occurs, droperidol should be interrupted and appropriate medical therapies should be initiated.
Tigecycline and increased mortality
Results from a pooled analysis from clinical trials reviewed an increased mortality risk associated with the use of intravenous tigecycline as compared to that of other antibiotics in treating serious infections. The cause of the excess death in these trials is uncertain, but it is likely that most deaths in patients with these severe infections were related to progression of the infection. However, the increased risk was seen most clearly in patients treated for hospital-acquired pneumonia, especially ventilator-associated pneumonia. tigecycline is approved for the treatments of complicated skin & skin structure infections, complicated intra-abdominal infections, and community acquired pneumonia.
Therefore, healthcare professionals should select alternatives other than tigecycline in patients with severe infections since the greatest increase in risk of death occurred in those patients who were prescribed with hospital-acquired pneumonia (including ventilator-associated pneumonia) or diabetic foot infection.
參考資料/References and websites：
https://www.hc-sc.gc.ca/dhp-mps/medeff/advisories-avis/prof/_2010/droperidol_2_hpc-cps-eng.php
https://www.thomsonhc.com/hcs/librarian/PFDefaultAction ID/pf.PrintReady
https://www.fda.gov/Drugs/DrugSafety/ucm224370.htm