They tell you to "limit" your alcohol to a couple drinks in a given day. I've heard there may be additional concerns if you have any history of symptoms of ulcers, but since I don't, I'm not super clear on that part. And I also think I've heard alcohol might cause or accelerate ulcers (not sure if that's worsened by being on Coumadin, or if alcohol just does that regardless).
I've had at least 2-3 (if not a little more) on several occasions since my surgery 6 weeks ago. No adverse affects so far. Yesterday, I probably broke all kinds of rules, lol. I had a couple of mojitos during the day at a Father's day outing. Then had a couple of beers early in the evening. Then had a couple more beers late at night. I had fresca or diet coke in between each "serving" so I "justified" it that way (probably not too smart). I've got an INR test tomorrow, so I'll let ya know how it goes - don't expect any problems though based on past experiences over the last 6 weeks. My buddy has a great idea I may try some time. Have 3 drinks, then start the clock for the next day and have 3 more - who says midnight has to be the end/start of a day
Seriously though, as I understand it, the main risk of alcohol (in addition to possibly causing/contributing to ulcers as mentioned above, which are bad if you're on Coumadin) is it thins your blood. When combined with the anti-coagulant effect of coumadin, it might make things a little more dangerous than normal if you got cut bad while still 'under the influence'. And further, my understanding is it's not so much the external cuts you have to worry about - they'll stop bleeding eventually, just will take a little longer than normal - it's internal bleeding that's a bigger concern (things like ulcers or concussions).
I think I've also heard it can affect your INR, and if I understood right, it causes some people's INR to go up, and others to go down. I haven't noticed that yet with mine - I've been consistently between 1.9 and 2.7 since surgery, which is pretty stable (if you're not familiar with the numbers). But if alcohol was ever going to affect my INR, it would probably be tomorrow (after having 6 drinks in a 24 hr period). I'm a big guy, so I've kind of figured 2 drinks for others is probably about the same as 3 for me... I know, I'm a rationalizer, lol. But I'll let ya know what my reading is in the morn.
I'd be very interested in others experiences with this though, as I am hoping to be able to drink more than just a couple once in a while. I'm not an alcoholic by any means, but sometimes it's fun to let loose. Just wondering how big the risk really is, and exactly WHAT the risks are.
But to answer your question - having "A" beer would most certainly not be a problem. And as far as other diet restrictions, vitamin K is what you have to be a little careful about, although I think most people would have to really binge on something high in Vitamin K to make much of a difference (although this may vary from person to person). There are a few foods (leafy, green things) and a few off-the-shelf things (Slimfast, Ensure) that have significant Vitamin K, which brings your INR down. So you either need to be consistent, and eat the same amount of vitamin K each week, and adjust your Coumadin accordingly, or, stay away from "binging" on those high Vit. K foods. That's my understanding anyway, but again would be interested in other's experiences with this (as I'm still pretty new to this myself).