How Coumadin interacts with other medicines

For any given person, any medicine can cause you to be more or less sensitive to Coumadin. Some of the drugs to remember are pain relievers (especially aspirin), antibiotics, and medicines to keep stents open (like Plavix). If you need one of these drugs, talk with your physician. If your physician prescribes a medicine, remind him or her you are taking Coumadin. If you intermittently take Chinese herbs, make sure you get frequent blood tests. (You probably should get blood tests every 4 weeks or more frequently, even if the INR is stable and no medicines have been started or stopped.) If there are concerns that the Coumadin effect may be changed, get an INR. Although the effect of most medicines is to increase your risk to bleed from Coumadin, some medicines can decrease the effect of Coumadin to slow clotting. That effect can also be estimated by doing the same blood test —the INR.