I am about to have knee surgery and I am on methidone and they are putting me under on anesthesia and I do not want to tell my doctor is it fatal?
Not fatal. you should tell them as it may affect your anesthestic requirements.
Truth is best. I'm thinking that Methadone is a step in the right direction for you. Also, if you care enought to fix the knee, care enough to get good medical treatment. They need to know your Rx history to do their best during and after surgery. Here's a similar query - you may have read it. I agree with the advice to tell the truth. https://answers.yahoo.com/question/index?qid=20110106140952AAF8WGg.