The objective of the study is to compare the efficiency of the opioid maintenance therapy according to the arisen of an acute painful phenomenon requiring an analgesic management for these patients. At first, this work will allow to determine the results on acute pain of the current practices for these patients. The comparison of the long term consequences on opioid maintenance therapy between the patients that presented an acute painful phenomenon and the control patients should help to improve acute pain management for these patients while limiting the risk of relapse in the abused consumption of psychoactive substances.