摘要
背景：之前研究發現美沙冬可能導致QTc波延長。 研究目的：本研究旨在研究使用美沙冬維持性療法，探討使用美沙冬前後QTc的變化，和劑量、各種變項和危險因子之間的相關性。 研究方法及資料：參與成員為海洛因依賴者使用門診美沙冬維持療法的患者，地點是在台灣中部某療養院。由精神科主治醫生使用中文版的MINI-SCAN診斷有無其他精神科共病。在計劃的第一天，所有參加者必須在經過培訓的精神科護士協助下完成一份自訴式的問卷調查。排除標準包括文盲，年齡不到18歲的患者。心電圖分析，由心臟科醫師單盲進行評讀。QT波間距長度使用Bazett公式校正心率。QTc間期延長被定義為男性大於450毫秒和女性大於470毫秒。如果QTc值超過500毫秒或QTc間期變化超過60ms有義意提高心律不整的風險。 研究結果：本試驗共收錄170人，其中男性155人（91.2%），年齡37.9±7.7歲，自訴有心臟疾病（4.7%），低血鈣1.8%，低血鉀，未出現低血鎂，有使用其他藥品7.6%。 使用美沙冬之後六個月，QTc的部份：由403.8±30.7毫秒，增加到420.9±46.0毫秒，增加17.1毫秒, p<0.001，QTc間隔延長部份，由原先5人，增加到21人，p=0.002，而QTc間隔>500毫秒者由原先2人（1.2%），增加到6人（2.9%），未出現TdP。 就QTc波增加數值部份與發現QTc變化與發現安非他命使用的天數呈正相關與原先QTc基準值呈負相關。這是之前研究所未發現的。由於此結果是否在探討methadone與心電圖中QTc變化時討論患者吸食安非他命的病史實在應該受到重視。 結論與建議：不過因為美沙冬本身與QTc波間距延長與造成TdP有相關性，小心調整藥品劑量，了解患者其他物質的使用史（如安非他命），有無其他藥品之間的交互作用，密切監測心電圖的變化，對於病患的安全才有所保障。
並列摘要
Background: Recent reports suggest that methadone may prolong QTc interval. Objective: The purpose of this study was to determine the effect of initiation of methadone on QTc interval in patients. Method:In this prospective study, we enrolled 170 heroin-dependent adults at a methadone maintenance treatment (MMT) programme at a psychiatric centre in Middle Taiwan. Exclusion criteria included illiteracy, age not reach 18 years, and diagnosis of mental retardation by a psychiatrist. Patients were followed clinically and electrocardiographically for QTc changes at baseline and 6 months later. Contributing factors for QTc prolongation such as medications, cardiovascular diseases, and electrolytes disturbances were documented. QT interval is corrected for heart rate using Bazett’s formula. QTc prolongation was defined as greater than 450 ms in males and greater than 470 ms in females. QTc value exceeded 500 ms or QTc interval changes more than 60ms indicate significant risk of arrhythmia. Results:Patients were predominantly male (91.2%); mean age was 38 years, 7.6% other prescription drug use, 4.7% self-reported cardiac disease, 1.8% hypocalcemia, 0.7% hypokalemia and no hypomagnesemia. The QTc interval increased by a mean of 17.1 milliseconds from baseline to follow-up (P< 0.001).No episodes of torsades de pointes were observed or reported during the study period. Significant increase in QTc occurred in duraction of amphetamine use, decrease in Baseline QTc value and no correlation with methadone dosages. Conclusion:Patients on long-term methadone maintenance treatment show longer than expected QTc interval values. ECG might be considered in ongoing MMT patients. Supports the recommendation that patients entering methadone treatment are screened for cardiac risk factors, aware of interactions between methadone and other drugs and duraction of amphetamine use.