I do frequent burping and hold upright for a while after my daughter eats. She won't swallow Zantac because of the taste. I tried the rice cereal in a bottle but it stopped her bowel movements. good luck!
Try feeding smaller amounts at a time. I did 2 oz every hour or two. I also kept my son upright for an hour after feeding. My dr recommended a teaspoon of rice cereal in his formula but that didn't help any.