So my Dad increased the dose to 3mg for 2 nights then went back to his usual 2mg. The INR was checked again and was 2.8. He continued taking 2mg for 4 nights and it went to 2.3 and today after 2 more days of 2 it was 2.1. His GP always says just take 2mg regardless of what it is, but other GP's have suggested alternate amounts. The anti-coag team at the hospital I work at say the same thing, that he may need to alternate 2/2/3 or 2/3 to account for the drops. They say there is a formulae to work it out, does anyone know anything about a formulae? It is something like the amount of Warfarin taken in a week and the INR results but I don't know anymore specifically. I don't like self dosing but sometimes you have to ensure the level is correct.