Infants had pH probes done before and after study medications. Compared to pre-study pH probe data, the PP group (white bars, n=4) did not show any improvement in measures of percent time with pH<4 (RI%) (A), the number of episodes with pH<4 (B), or a combined score (C). In contrast, the OB group (n=6) showed a decrease in RI% (p=0.028), a decrease in episodes (P=0.028), and a decrease in score (P=0.07). The OP (n=3) and BP (n=3) groups also showed a decrease in RI%, episodes, and score, but with the smaller number of patients these improvements did not reach statistical significance.