The four new drugs have better safety profiles than warfarin, and some are more effective than warfarin for stroke prevention in people with atrial fibrillation. In a remarkable five years spanning 2010 through 2014, four novel oral anticoagulants underwent pivotal trials for stroke prevention in atrial fibrillation, as well as treatment of pulmonary embolism and deep vein thrombosis. Multiple algorithms and even genetic testing have been undertaken with the hope of deriving an easy-to-follow dosing scheme, but these efforts were disappointing overall. Patients and health care providers complain about the difficulties and inconveniences of trying to use warfarin properly. Even when the INR tests within the desired range, catastrophic bleeding complications, such as bleeding into the brain, can still occur.

This approach is slow, cumbersome, and frustrating. If the INR is lower than 2.0, the warfarin dose is increased to prevent excessive blood clotting. If the INR is greater than 3.0, the warfarin dose is decreased to prevent excessive bleeding. Standard-intensity anticoagulation with warfarin is usually targeted to achieve prothrombin blood test results, expressed as international normalized ratio (INR), within a range of 2.0 to 3.0. The optimal dose is determined by monitoring the level of anticoagulant in the blood. Warfarin is plagued by hundreds of drug-drug and drug-food interactions. Whereas insulin causes low blood sugar, warfarin is notorious for the complication of major bleeding.

Along with insulin, it is responsible for the most emergency hospitalizations due to adverse drug reactions. No other oral anticoagulant was successfully developed and marketed in the United States until 2010. This anti-clotting drug commanded national attention when President Dwight Eisenhower received the drug as part of his treatment following a heart attack.

The oral anticoagulant warfarin (Coumadin) became available for prescription in 1954.

Inr antidote