美沙冬替代療法(Methadone Maintenance Therapy)是以生物、心理與社會醫學為基礎，使用與海洛英類似藥理作用的替代藥物-美沙冬，經口服使用以補充海洛因成癮者體內內源性鴉片量的不足。以低成癮性藥物代替高成癮性毒品；以低毒性藥物來取代高毒性毒品；以長效藥物代替短效毒品。以下介紹本院兩件個案，一為疑似長期服用美沙冬導致的肝毒性，另一為用藥疏失導致美沙冬過量中毒，本文亦介紹美沙冬中毒處置與提出本院如何預防美沙冬用藥疏失以預防類似之疏失再度在本院或他院發生。

Methadone maintenance therapy (MMT) is based on biology, psychology and social medicine to reduce illegal heroin use. MMT applies low addition to replace high addition; low toxicity to replace high toxicity and long duration to replace short duration. We reported two cases about MMT in our hospital. One is hepatic toxicity induced by suspected long-term MMT and another is methadone overdose caused by medication errors. In this article we also introduced treatment of methadone overdose and suggested how to prevent similar medication errors of MMT that maybe happened in the future or in other hospitals.