Prevacid Dosing

My son Jasper (4 months, 12 lbs) is just switching from zantac to prevacid ( half a solutab 7.5 mg twice a day )

From what I’ve read, the switch can be pretty rough if you cold turkey the zantac (which we did) because the prevacid takes 3-7 days to kick in. However, his spit up was no longer acidic with in the first 24 hours. Is that normal? Should I talk to his doctor about reducing his dose?

It’s been 4 days now and I’m still waiting for a steady state because he had kind of been all over the place (starving, refusing to eat, gassy, sleeping poorly, then lots etc.)

Thanks for your help,

Amy