Welcome! First off, how long have you been on the Prevacid? It can take up to 2 weeks to see full results on Prevacid. Also, I assume you have the solutabs. Make sure you are giving them 30-60 minutes before meals and on an empty stomach. You have to give them this way in order for it to be most effective. I would stay on the Prevacid and give it it’s time.
While you are waiting for the Prevacid to “kick in” you can still give the Zantac. If you don’t, it will be like your little one is on no meds at all. Just make sure you are giving the Zantac and Prevacid spaced at least 4 hours apart from each other.
Nothing short of time or surgery will reduce the actual spitting up. Your goal should be to make your little one comfortable until then. Good luck!!