Al, antibiotics and warfarin

[Karlynn]

We know that antibiotics most often raise the INR, but from your response to Perkicar's thread on Bactrim it sounds like some are more infamous than others in raising the INR.

What antibiotics are the worst at raising INR too high (and should be avoided if possible), and which ones don't cause the INR to spike too high.

[Randy & Robyn]

I would also be very interested in knowing this. I would still like to get a mechanical if at all possible but because of the brucellosis, I will be on three antibiotics for possibly a few years. Daptomycin and ofloxacin are the current two. Another will be added in a week when I am off the iv gentamycin.

I'm betting warfarin would make things very difficult for me now.

Randy

[Ross]

Until Al gets in here, when I was sent home with my lovely PICC line and pump with the vancomycin, Bactrim, Rifampin and about 4 other antibiotics as well as coumadin, all I can tell you is, it's a huge juggling act. It's not impossible to do, but it was not easy and I'm not going to say it was.

[allodwick]

Raising the INR:
Fluconazole (Diflucan) and anything else with "azole" in the generic name. INRs above 8 are quite common with these. Even 1 day of a vaginal suppository can raise the INR

Bactrim, Septra, SMX-TMP DS, sulfamethoxazole-trimethoprin

Z-Pak

Lots of others such a Cipro are associated with a high INR but it is hard to figure out if it is the drug or the fact that the person is sick and not eating or exercising as usual.

Lowering the INR - these require the warfarin dose to be increased to 5 to 6 time what it was before therapy. If you were on 5 mg daily, you could need 25 to 30 mg/day with these and it can take months after the drugs are stopped to get back down to your previous warfarin dose.
Dicloxacillin
Rifampin
Nafcillin - an IV antibiotic

[catwoman]

Al:

Thanks for the great info!

I'll be happy to test the Cipro theory, if y'all will chip in to send me to Mexico City for a mini-vacation.:D
Four years ago, a cat club in Mexico City flew me down from Dallas-Fort Worth to teach them how to put a show on using our association's rules. (The club had previously been affiliated with a European cat registry association.)
To be on the safe side, my PCP had me take Cipro several days before and during my trip to prevent any possible GI problems in a strange country.
I ate at very good restaurants, which served bottled water & Coca-Cola.
Didn't get ill.

[Karlynn]

Thanks so much Al!

I didn't know that there were some that could lower an INR that drastically. I assumed (and you know that old joke;) ) that antibiotics all had the potential of raising it.

[allodwick]

Antibiotics are like people - some pick you up and some let you down.

[LUVMyBirman]

Never had an antibiotic INR related spike. Have been though the gamut with various drug classes. ALL effects have been a decreased INR. Even with the heavy duty IV's.

On to the antifungals. Use Monistat 7 for instance. My INR spiked to 8.1! And was very slow in coming down. Took almost a week to level down. And 3 weeks to get back on track.

[allodwick]

8.1 is a "spike".

I don't like it when people say that they spiked a 4.0 - that is a thumbtack not a spike.