Q. I have a horrible urinary tract infection. The doctor put me on Macrobid but after taking it for a week, I still have the infection. I was given a prescription for 7 days of Septra.
I am on warfarin. Will the Septra work? I am desperate and in pain!
A. Contact your doctor immediately! He will likely tell you to stop the Septra (SMZ-TMP or sulfamethoxazole plus trimethoprim), as it can lead to a potentially life-threatening interaction with warfarin (Coumadin).
This antibiotic is among four commonly prescribed drugs that can potentiate warfarin to cause dangerous bleeding (Consultant Pharmacist, March 2009). The others include fluconazole, metronidazole and amiodarone.
Warfarin interacts with many drugs, foods and herbs. Anyone taking it should double-check before starting a new treatment, since so many compounds are incompatible with Coumadin.
