Magnesium or antibiotics interacting?

[Bridgette]

Hi

On the 20th March I checked my INR on my Coaguchek and it was 3.0 which was just right (range is 2.5-3.5).
I just checked it again yesterday and it was 2.1 so has dropped a fair bit. I was on short course of antibiotics (have been sick with bronchitis) and also I have started taking magnesium to help regulate my heart (I am pretty pleased with how it has helped).
Could either of those drugs lowered my INR or maybe it has dropped because I have been sick?
I have been taking 4.5mg daily, so I have upped it to 6 for a few nights to get back up in range, and was thinking of testing again on the 3rd April.

Hope I am on the right track

BTW I have an ON-X mitral valve - oh, and I have started taking a 100mg Aspirin daily (have been doing that for about 2 weeks).
The antibiotics I took were Augmentin (amoxycillin/clavulanic acid)

Thanks
Bridgette

 

[Ross]

Everything your saying should have caused a rise, so I'm thinking the test was bogus and try again. My bad, Augmentin didn't affect my INR, it was Keflex.

Nonetheless, test again as I'm thinking it was a bogus test.

 

[Bridgette]

Thanks Ross. I tested again today and it was 2.4 so just to double check I went to the clinic and had a test done - the nurse just rang and said it was 2.1.
Maybe I am one of those people who need more Warfarin or something.
I stopped taking the Augmentin about 5 days ago.

Whose results would you regard as more reliable, the Coaguchek or the clinics? I know that at the clinic the blood is sitting around for a while till the courier comes to take it up to the lab, so maybe the Coaguchek is better?

Bridgette

 

[Ross]

You can't compare to an exact degree, between machine and lab. You could test twice with your Coaguchek and get the same results, so I would say they are equally accurate. Basically, you'll seldom get the same results if tested back to back. There is almost always a .2 or .3 difference. The same would hold true for back to back lab testing--They aren't going to get the same numbers twice either.

Sounds like you need to have your dose bumped up 10% over the week and then retest.