It was not difficult for me to change between them. Prevacid always worked the best for me for the better part of 22yrs until my hiatal hernia started enlarging again and I needed a re-repair last Jan. Just be sure you are taking B12 in methylcabolamine form. When your on these proton pump inhibitors (PPI) your body will not absord any protein bound B12. Our bodies need a high pH in the the stomach to release B12 from protein so that it can be absorbed in the gut. PPIs prevent this high acidic environment. Our bodies will absorb 1% of non-protein bound B12 ie a sublingual tablet. Mega dosing is needed to come close to the daily amount of B12 required. Worse case scenario severe B12 deficiencies lead to dementia. There are articles out there that discuss this as well as an increase risk for C-diff. So it's important to take a probiotic as well. Good luck.