Jean Melbourne,   Thanks for your questions.   First let’s discuss the lip discoloration.  Warfarin is a blood thinner whose major side effect is bleeding.  It is possible that she could be bleeding into her lips, but this would be easy to determine as the blood would eventually leave the lips themselves and migrate into the surrounding tissue.  As the blood resolves, it would turn green, then yellow.  Also, the bleeding would cause swelling.  I think this is unlikely.   You mentioned that when you Mother is breathless, her black lips are noticeable.  This, more likely, is caused by a lack of oxygen in her blood stream.  She may be breathless for any one of a number of causes: heart disease, congestive heart failure, slow pulse rate, lung disease.  This should improve as her breathlessness improves, or she is given oxygen.    Your Mother is on digoxin to help control the atrial fibrillation, and in rare cases help keep them in sinus rhythm.  More likely it is being used to control the rate.  The warfarin is a blood thinner that is used in this situation where the risk of developing a clot from heart is very high in patient with atrial fibrillation.   Your description of your Mother’s vision problem is the classic description of a phenomenon known as amaurosis fugax.  This is a form of a mini-stroke or TIA (transient ischemic attack).  This may be from the atrial fibrillation and the formation of a clot that has travelled to the eye.  Or it may be a clot or cholesterol placque from another source (the carotid artery, the aortic arch) that has traveled.  Perhaps the warfarin dosage is inadequate and needs to be titrated to a higher level.   Your Mother’s doctor needs to know about all of the above.  He will be able to determine with a simple blood test whether the Coumadin dosage is adequate, and he may be able to assist in the breathlessness.  Also, you Mother may be at a point where supplemental oxygen may be required on an as-needed basis.   I hope this has been helpful.   Best wishes.   Martin Cane, M.D.