I took my first generic protonix yesterday and I've never been so sick & dizzy I called my Dr. back and told him I wanted the real protonix back & i'd be happy to pay the difference !I almost ended up in emergency room with digestive pain and heartburn etc. Finally figured out that I had just started generic Protonix. Now I know what my problem was. Went to doctor today and got new prescription for brand. Be very careful with this generic.