I was on prevacid and I did not like it. It cuts down on the acid your stomach is producing and while it helped the heartburn, I had a hard time digesting my food!
Have your daughter tested for food allergies or intolerances. Once I cut the foods out I was allergic to the reflux stopped. If you don't want to get her tested you can do it yourself by the "elimination method." Google it, you have to elimiate all allergens and then slowly add them back in and see which ones are reacted too. Also, a food allergen can affect the person up to 4 days after it is eaten, so it's hard to tell what someone might be allergic to!
Probiotics ARE wonderful! I highly suggest you skip the prevacid (like the other poster suggested) and get on a good probiotic as well.
Kombucha tea has also helped me. You can get it at the health food store or Whole Foods, it's a fizzy, fermented drink. Have your daughter start on only a very small amount (1/4 cup) and slowly build up. If she drinks too much at once she could get sick. Kombucha tea is not actual tea, and has friendly bacteria that our bodies need.
Good Luck!