Its "bar-ba-TUR-ate" if you went to med school at HAHVAHD or Yale or interned at the Cleveland Clinic or some other such bastion of uppah class medical science (they don't practice mere medicine, you know, its science. Even though Hipocrates spoke as much of the art of medicine as the science, that part has been erased over the eons. Personally, I'd rather have the artiste).

Those less elevated docs that I worked with, lo all those many years, still said "bar-BIT-u-ate."

Either way, you can still make a funny story out of it with a little poetic license.