Just returned from a stay at the hospital for deverticulitus. They gave me antibiotics of course and a regimen of them once I got home. They did not tell me my INR would change or had changed and so when I got home I went immediately back to my schedule that I had before,7.5mg/day keeps me around a 2.5 . Monday arrived and I recd a finger prick test from my cardiac MD which showed it to be quite high like way high..4.8 I was instructed to stop for three days entirely and then resume on a smaller scale until we got back to normal which is 2.5 for me. Its really a good idea to make sure your antibiotics don't screw with your INR.