Antibiotic effects

[sue943]

I know that antibiotics rasie the INR, my GP told me so when prescribing. I took a course of antibiotics a couple of weeks ago and when I was tested last week, wonder of wonders, my INR was up where I would ideally like it to be, it was 3.6. For some weeks I have been on a slightly increased dose of warfarin so appreciate that this might have something to do with it.

What I want to know is does the antibiotic just raise the INR while you are taking it? I am on another course of antibiotics so guess my INR might go to the high end or even out of my range this time.

 

[Ross]

Not all antibiotics will cause a rise. What are you taking? Generally the rise only occurs while taking certain antibiotics.

 

[Emma]

Chloe has had amoxicyllin and that doesnt seem to raise her INR at all, although it apparently can do. She's also had cefaclor which has also had no effect on her INR. But when she had co-amoxiclav (a combined antibiotic) that did send it up while she was taking it.

 

[ccrawford]

The antibiotics that raise the INR do so by affecting the bacterial in the digestive tract that produce vitamin K. They reduce the amount of vit K and this causes the INR to rise. I do not know of a complete list of the antibiotics that affect INR, but you can dig them out of any of the drug interaction sites on the net.

 

[sue943]

What I want to know is does the INR just increase while you are taking the antibiotic, how long after you finish the course will the INR decrease?

I am very happy with my increased INR, it is now perfect.

 

[Ross]

As soon as the good bacteria in your digestive system begin to multiply again, the INR will return to normal. A day or two after stopping the antibiotic.