Reflux and Enfamil AR

My daughter is 12 weeks, she has had reflux since 6 weeks old. They put her on Zantac and that helped almost 100%. Until now, all her reflux symptoms are coming back, puking, fighting the bottle, choking on it. Fighting her burps, crying during feeding. I called her DR, to see if her meds needed to be increased. She recommended Enfamil AR( shes been on Similac sensitive since the beginning). I heard the Enfamil AR can cause constipation, idk if i can do that to my poor girl who suffers terribly from gas. I have to put mylicon in almost every bottle of hers. Isnt added rice for olser babies. Like 4 months old? As they start getting solid food introduced?

Has anyone had any success with enfamil AR and reflux?