Zantac works best if given 30 minutes before food. Zantac and Prevacid needs to be given 4 hours apart. You could do prevacid at 8 am, Zantac at noon and 4 and prevacid at 8 pm. I would ask for a prescription for Zegerid to replace the prevacid. . Much more effective and you should be able to get rid of the Zantac.
zantac can be given at any time, but best if given on an empty stomach…but you can try whenever you find it’s necessary- You’ll find that it can take some experimenting w/ timing/tweaking things…You can check zantac dosing here (& pepcid, too):