Hi ET,
I have not had any issue with alcohol and INR since going on warfarin 7 months ago. In a typical day I will usually have one or two glasses of wine and I almost always stay in range. I self-monitor and I like data and feedback, so I have tested to see affects from various amounts of alcohol. I'm not generally a heavy drinker, but I have had a few days watching the fights where I might drink 5-7 beers. I have noticed that on the morning following that many drinks that my INR does inch up, but not to alarming levels. I might have been consistenly at INR of 2.5 and the morning after having several drinks I might be about 2.8, for example, which would still be in my target range of 2.0-3.0 and then the next day it will be typically back to 2.5.
I have also experimented with dropping my dose just a little, if I believe that I might have several drinks that day- for example from 7mg to 6mg. I have found this to work well for me in keeping my INR from changing due to a day with more than normal alcohol consumption. I'm suggesting that anyone else do this, but it has worked for me if I want to avoid even a small upward movement of INR.
I think what you want to be careful of is if you don't drink much, then go on vacation and drink heavily for several days in a row. There have been case studies of people who have had problems in doing this type of behavior. This is one of the real benefits of self-testing, because if you were to go on such a vacation and were to drink more than normal for several days, you could work in a couple of INR spot checks during to the trip to make sure that you are staying in range.