I've taken several medications during a depression and then slowly went down to only one when the depression resided. Perhaps you're in a really severe episode and need lots of meds at the moment, but later you'll go off them?

Why not just tell your doctor that you don't want to take a certain medication? It's not like he can force you. He can give you the little doctor speech, but ultimately it is your body. In fact, if he's worth his degrees at all he'll suggest something else. It seems that medications for bipolar disorder are pretty scary and a good doctor would understand that and understand that it's important for you to be comfortable with what you're putting into your body. Research alternative medications and see what he says.