Drug Uses Coumadin is used to prevent and treat a blood clot that has formed within a blood vessel (thrombosis) or in the lungs (embolism). Usage Take Coumadin exactly as prescribed by your doctor and ensure that your condition is monitored by the doctors on a regular basis. Missed Dose You should try and take your doses on time taking care not to miss any. But if you do miss a dose, then skip it and continue with your regular dose. But do not take a double dose. Storage Store it at room temperature away from heat, moisture, and light. Overdose Abnormal bleeding or bruising and blood in the vomit or stools are some of the common symptoms of a Coumadin overdose. More Information The drug may cause light-headedness, dizziness, and faintness in some people. Do not consume alcohol along with the drug. Do not drive or handle heavy machinery until you know how to react to the drug. Only use if prescribed.