I'm sorry but I don't know the exact answer to your question. I experienced some mild hair loss on topamax too but I'm off it now. I have heard some negative things about rogaine. I heard that it actually doesn't help hair loss but just continues it by making you lose more if you stop using it. Don't know that for a fact, but I just don't want your hair loss to be worse.
Does your hair fall out like all the time or just in the shower? Mine only fell out in large amounts when washing.