Welcome to the board Toodle
What side effects are you experiencing?
I've tried doing a search which came up with Tegretol (carbamazepine) but you really need to speak to your doc as I do not know about meds. I'm sure they will understand that it's imparing your quality of life. They might give you an alternative or they might give you something else to combat the lithiums side effects.
Let us know how you get on , take care ,