I don't think you need tums when plugging an oxy, its not absorbed in your stomach whatsoever when plugged, it bypasses it completely and goes straight into your rectum, where it is absorbed and therefore, works better without having to worry about the contents of your stomach.. I mean, if your taking it oral, I can see taking antacids to make it work better.. I do it with Adderall, everyday! It doesn't work right on an empty, acidic stomach... much better if your stomach as a basic-neutral pH, and isn't completely empty.. bananas, water, and tums... bread.. things like that, are good to eat when taking pills orally, that can be fucked up by having stomach acid which I know is true with Adderall, never noticed with oxy... I never really took oxy oral, when I did take it, but when I did, I never noticed it worked differently when I took/didn't take antacids, I totally believe it.. I just rarely took it oral, mostly sniffed, smoked, plugged, and IVed it.. but oral oxy, even though it has a great BA that way, never left me feeling that "satisfaction" feeling I longed for with that drug, when I used it.. haven't touched it in over a year, year and a half though now.. don't plan on it either..
All I know is, plugging oxy, the correct way, with a small oral/needleless syringe of some sort, mixed with water, works fucking awesome! Truly, one of the best ROAs you can take oxy... IME.