I've used all 3 at one time or another,Tagamet,when first diagnosed.Then doc said Tagamet was and older med and more expensive.Then he switched me to Pepcid which didnt work for me at all.Then i was switched to Acidphex,which gave me stomach pains.Then was switched to Zantac and on it for yrs,Then the doc took me off it and put me on Prevacid,which works great for me.I take 1 pill a day and i can eat just about anything i like if i forget my pill im in trouble.Hope this helps.Take care