Both drugs are in a different class and do different things, so the dosage of one doesn't effect the dosage of the other. I the welbutrin isn't working for you, I would ask about it. Not all anti-d's work for everyone. There may be a different one that would work better. I know many cysters take a stronger amount of met., but I think each are so individual that it's probably hard to say. Hope you can tolerate the stronger dosage of met. if that's what you need. Good luck
