After 3 years of having an INR result of 2.5 - 3.0 which is right in my appproved range I have suddenly got a reading of 5. I am very careful with my diet etc and have not changed it at all recently. No bingeing or heavy drinking! I have not been on any other medication eg antibiotics. I am on Warfarin for life following 2 DVTs and PEs and had Bowel Cancer 5 years ago. Any ideas please?