Conversation: The conversation between human and AI assistant.
[|Human|] My son has been on Coumadin for five years after the placement of his aortic valve with an Onex valve. Not sure of that spelling of the valve. Now he has dark discoloration of his skin around his ankles and lower part of his legs. Is this to be expected with the use of Coumadin? My email address is YYYY@YYYY
[|AI|]  Hi & Welcome. Coumadin (Warfarin) is an anticoagulant (blood thinner) which reduces the formation of blood clots and is used to treat or prevent blood clots in the blood vessels or prosthetic heart valves like On-X aortic valves to reduce the risk of stroke or other serious conditions. Based on the history given, your son seems to have developed bleeding underneath the skin that has resulted in dark discoloration around the ankles. Bleeding is one of the most important side effects of Coumadin. So, consult his treating physician to adjust the dose of Coumadin in such a way to have a normal prothrombin time and International normalized ratio (INR) in the range of 1.5 to 2.0. Hope the advice given above would be useful in preventing the side of bleeding caused by Coumadin. Best regards.