I was on Prilosec for over ten years when my insurance company took it off their formulary, and switched me to a generic. I haven't had any problems with the generic, other than that which I experienced with Prilosec, except slight hair loss. I changed generics, and that stopped. However I firmly believe that this drug is addictive, and I cannot function without it. The insurance company calls it a currative, and my doctor calls it a maintenance drug. The doctor says I will be on it the rest of my life, and the insurance company only approves it for 10 week period of time. I have tried Nexium and can tell no difference. I learned at the beginning how to adapt to the side effects of brief periods of nausea, and constipation.