Tetracycline like most antibiotics will affects your INR to some extent. One of the side affects beyond the INR is a rare change to develope hypoprothrombinemia (increased risk for bleeding).

I was on tetracycline several years ago when it was the choice antibiotic for lyme disease. I was, and still am, on Coumadin so they monitored my level to ensure it didn't adversely change.

As it turned out the deer tick didn't have lyme.

Regards,
Tom in Connecticut

When I started on Coumadin.I developed a pretty moderate case of Rosacea. It was very disheartening along with all the other pain, changes and discomfort. I have been on a therapeutic dose of 50 mg. of doxycycline daily for months. When I told my Dr. that the Coumadin was causing my face to go insane he kind of yelled at me and said well you have to take the Coumadin! "this is a life threatening condition" so I cried..he looked at my face and agreed it was too serious of a case for Metrogel cream or anything else to help so he put me on 100 mg for two weeks and then sent me to dermo who has me on the maintainence dose, MY INR;s have been mostly ok. I also get the occular roseacea from time to time and really making sure that I stay out of the sun does help somewhat but it is very frustrating. I am assuming that doxycycline is similar to tetracycline and hopefully it is like vitamin K in the sense that if you consistently take it , than your blood levels will also level out? Good luck . Tom, have you heard of Coumadin causing or exacerbating Rosacea or was it just something that was going to happen to me anyway and not related to the DVT and treatment? I was just wondering. I can't find much on the internet about it and haven't seen it as a Coumadin side affect. ubless I missed it ..I try not to read them.

Thanks for the very helpful feedback.

I'd be very interested to know if coumadin exacerbates, or can bring on, ocular rosacea. My rosacea has been very minor for years, controlled with very infrequent metro cream, but the ocular rosacea began after I came home after my surgery and being on coumadin for about 2 weeks.

And the ocular rosacea is much more difficult to deal with on a day to day basis than the holes in my head (well, not holes, they're more like dents) or the DVT. I do realize the DVT is a more serious medical issue but I can largely ignore it now that I've got the diet/INR thing pretty much under control. Or at least I did...