Method: A randomized, single-hlind and controlled study was carried out, dextromethorphan plus Methadone were applied in study group (N=25) and only Methadone in control group.

• 方法采用随机单盲对照试验设计,试验组25例采用美沙芬与美沙酮合并用药,对照组25例仅用美沙酮。