... switch because I lost my medical insurance and the Venlaxafine was $254. How long will I feel like this? This has nothing to do with Surgery! I had been on 150mg of VenlafaxineER for about a year. When my last scrip was gone, I called my doctor's sec'ty and asked her to ask the Dr to change me back to 40mg of Citalopram, which is what I was on for about a year before she changed me to the Effexor.