cymbalta is brand name of antidepressant duloxetine which has half life in body of 8 to 17 hours, means it requires average 12 hrs for its concentrtion to become half after oral intake... when u take it regularly the steady state plasma level is achieved n it require at least 24 to 40 hours for drug to be cleared from the body. the strategy u ve started to avoid the discontinualtion symptoms of cymbalta is appropriate n good.. actully cymbalta causes discontinuation symptoms because it has lower half life while prozac has half life 4 to 6 days after chronic administration. so take prozac regularly for 15 days and then keep it alternate day n then if u want to stop it, stop after another 15 days it wont cause discontinuation symptoms because of the long half life..