I am long term opioid dependent and currently on Suboxone. I am considering a shift to go back on Methadone. Problem is when I was previously on Methadone (90mg once per day) I was going into withdrawal early, lethargy and anxiety. It felt like the methadone was being metabolized too quickly in my body. When I was on the Methadone (90mg) I was also taking Effexor (venlefaxine) 150mg. Could it be that the venlefaxine is metabolizing the methadone too fast? Thanks for any help on this.....