Introduction. Warfarin is the main oral anticoagulant used in the UK. Oral means it's taken by mouth. An anticoagulant is a medicine that stops blood clotting. Factors such as aging capillaries or thinning skin, and even certain diet supplements and medications( aspirin, warfarin, etc) may cause easy bruising. Bruising may also indicate something more serious, such as a blood-clotting problem or a blood disease. Warfarin can cause severe bruising, especially if the level of the medication becomes too high. Cortisone medications, such as prednisone , promote bruising by increasing the fragility of the tiny blood vessels in the skin. Zocdoc › Answers › What type of bruising do I need to be worried about while on blood thinners? Question I am currently taking Warfarin because i have Blood Clots in my lungs/ Pulminary Embolisms. On the other hand, the side effects associated with warfarin (such as Coumadin®) blood thinners are numerous and well documented. Read More Antiplatelets do not have as many risks as anticoagulants, and do not need weekly blood checks for INR, but there can be side effects such as bruising and excessive bleeding. In adults with unexplained bruising, bleeding, petechiae, or hepatosplenomegaly consider arranging: A very urgent full blood count including platelet count (within 48 hours) and blood film. Clotting screen (prothrombin time [PT], activated partial thromboplastin time [aPTT], and international normalized ratio [INR] if the person is taking warfarin). A Whole Lot of Bruising Going On A 72-year-old man is your last patient of the day. He is visiting his daughter, a patient of yours, who asks you to see him. Older people also are more likely to take aspirin, clopidogrel, warfarin, or direct oral anticoagulants, which make bruising and bleeding more likely. Key Points Excessive bleeding may occur on its own or after minor injury. Why the Sudden-Onset Bruising in a Previously Stable Warfarin Patient? Douglas S. Paauw, MD. Disclosures. December 12, 2014. Warfarin Interactions As many clinicians know, TMP/SMX and warfarin. Easy-to-read patient leaflet for Warfarin. Includes indications, proper use, special instructions, precautions, and possible side effects. Includes indications, proper use, special instructions, precautions, and possible side effects.