I have to chime in here, as I've been on several of the PPI and acid-pump inhibitors for about five months now. They keep having to change me, because even though I need them (I was probably close to an ulcer before, needing Tums(tm) every night, in constant pain, etc.) I believe they've affected my INR and also they've brought back my migraine frequency. For quite some time there, I was having little or no migraine attacks, but unfortunately since starting this class of drugs they've returned. I'm still trying to learn more about that aspect of the drug. Migraine is listed as a side-effect according to my neurologist. My protime is another matter - I've seen a steady drop in my number since starting the prilosec OTC. I think my coumadin clinic is managing this well, bumping up my dose slowly and now I'm finally back in range.
But nothing else major has changed, so for now I'm believing the prilosec DID have an affect on my INR. Of course, everyone's different in this realm.....