Are you doing all the other interventions like holding her upright during feeds, burping frequently, keeping her upright at least 20 minutes after a feed, sleeping her in an incline, etc...?
Did you notice any improvements with the zantac
? Before the zantac
did she have signs of *acid* reflux (screaming when burping, arching back in pain, etc....?) I ask because some doctors do prescribe zantac when there aren't signs of a problem with acid, only spitting up.