How long does Coumadin remain in my system after stopping therapy?

Hello.

Coumadin (warfarin) is an anticoagulant that thins the blood to prevent blood clots. The half-life of warfarin, the time it takes for half of the drug to be eliminated from the body, is approximately 20 to 60 hours, with an average of about 40 hours. However, the duration of its effect (anticoagulation or blood-thinning effect) can persist beyond the time it takes for the drug to be metabolized and eliminated.

After stopping warfarin:

Elimination: Given its half-life, it generally takes about 5 half-lives for a drug to be substantially removed from the body. This means that it can take approximately 3 to 5 days for warfarin to be eliminated from the system.
Anticoagulation effect: The anticoagulant effect, as measured by the International Normalized Ratio (INR), usually begins to decrease within 24-48 hours after discontinuing warfarin. However, the return to a normal INR or normal coagulation status can take several days, and sometimes longer, especially if your INR was significantly elevated.
Individual Variability: The duration that warfarin remains in the system can be influenced by several factors, including the individual's metabolism, liver function, other medications being taken, diet, and other factors.

Hope this helps.