Azithromycin and INR

[Computec]

There seems to be a lot of contradicting information regarding the effect of azithromycin on INR levels. One website says "Oh Yeah... ! Big time." while another says "Nope. Not at all."

Well, I'm going to be the guinea pig on a study of my own. (Like MOO said, "...between test and hemorrrhage." Today I was prescribed a 5 day course of azithromycin starting with the standard 500 mg and then followed with 250 mg per day for 4 additional days. I also had a blood draw for my INR reading before starting the antibiotic. (Results to be known tomorrow.)

Generally speaking my INR is pretty stable (2.5) with variations of a few 10ths. My cardiologist has tried to get me to go 6 weeks between readings but I didn't want to go that route just in case. A second INR reading can be taken on day 4, Monday. between dose 3 and 4. Then, taking Al's advice, I'll have it checked again on the following Saturday since the last dose would be on Tuesday. Barring some hideously long half life, the INR shuld return to an approximation of normal by then. If Monday's INR test shows a significant increase (Results known on Tuesday,) I'm sure my INR manager will require me to cut the dosage or hold a dose. Won't this be like chasing the numbers and not a very good idea?

If I don't change my diet or increase my exercising for the next week I think this should be a valid test but then everyone is different in how they metabolize drugs. Considering that it took 6 days in the hospital to get my INR up to 1.9 originally I assume I'm slow on the uptake in more ways than one. My last course of antibiotics seemed to have made my INR drop by 2 tenths. Go figure.

Any thoughts on this or am I just spinning my wheels?

Jerry

 

[ALCapshaw2]

I will be awaiting your results as I take 500 mg of Azithromycin prior to my Dental visits. NO problems to date, but I do NOT test in the near term either...

'AL Capshaw'

 

[Ross]

INR testing can vary widely, so 2/10th's really isn't even conclusive of anything, that could be normal.

http://www.warfarinfo.com/azithromycin.htm

 

[catwoman]

Jerry:

I haven't had to take zith since going on warfarin. But I have had other Rxes & steroid shots for a URI, sending my INR up. Home-testing allowed me to temporarily tweak my warfarin until my INR went to a more even level.

FWIW:
You say you're pretty stable at 2.5.
The range for mechanical mitral valve is 2.5-3.5. I become nervous when my INR gets down to 2.5. I prefer to keep mine at the higher range, even over that, 4.0.
We say here that you can replace blood cells but not brain cells. My PCP concurs, saying that too many medical professionals get hung up over the prospects of a bleed rather than risks of a clot. I'd rather have a few bruises than a stroke.

 

[Guest]

The zith should affect the INR. I know that sometimes it doesn't but I can't figure out why.

 

[Computec]

Well, this just goes to show you that everyone is different.

My INR pre-azithomycin was a 2.7 and my INR after the fourth dose (80 hours) was also a 2.7. For an antibiotic that's known for having an effect on INR it didn't even budge mine. I must have intestinal bacteria with the constitution of Conan the Barbarian.