Known interactions between the following drugs: Coumadin, Levaquin

Although the cause of this potential interaction is not clearly understood, levofloxacin may increase the anticoagulant effect of warfarin. Warfarin is generally used to prevent your blood from "coagulating" or forming blood clots. When levofloxacin and warfarin are used at the same time, your blood may be much less likely to clot and this may increase the risk of excessive bleeding. If these drugs are taken together, your doctor may want to monitor you closely when therapy with levofloxacin is either started or stopped. Blood tests can be used to make sure that you are getting the right amount of warfarin. If you are experiencing problems, it may be necessary to adjust the dose of warfarin. Your doctor may also consider switching to a drug that is similar to levofloxacin, but that is less likely to cause problems with warfarin. Ask your healthcare provider about these drugs and this potential interaction as soon as possible.