Tablet. Warfarin 0.5 mg Tablets are white, flat round tablets, with a 7.0 mm diameter, plain on one side and scored on the other, engraved with “W” above the score and “0.5” underneath. Tell your healthcare providers that you take COUMADIN, and about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Some medicines may affect how COUMADIN works, or may increase your risk of bleeding. Coumadin® (warfarin) can interact with many OTC (over-the counter, non- prescription), and herbal medications which could increase your risk for either bleeding or clotting. What other drugs will affect Coumadin? Many drugs (including some over-the-counter medicines and herbal products) can affect your INR and may increase the risk of bleeding if you take them with Coumadin. How to use Coumadin. Read the Medication Guide provided by your pharmacist before you start taking warfarin and each time you get a refill. If you have any questions, ask your doctor or pharmacist. Many other medicines can interact with Coumadin and affect the dose you need or increase Coumadin side effects. Do not change or stop any of your medicines or start any new medicines before you talk to your healthcare provider. What to watch out for: By far the most common side effect of Coumadin is abnormal, and sometimes profuse, bleeding. The bleeding is most likely to occur inside the eye or in the intestines, however, bleeding and easy bruising can occur anywhere in the body, including the brain. Foods containing vitamin K affect how Coumadin works. Green leafy vegetables contain a high level of vitamin K. Increased consumption of vitamin K containing foods decrease the blood thinning effect of Coumadin. Many medicines and herbal products can interact with COUMADIN and affect the dose you need or increase COUMADIN side effects. Do not change or stop any of your medicines, or start any new medicines, before you talk to your healthcare provider. Illness, diet, changes to your medicines, and physical activities may affect the results. Tell your doctor if your health, medications (prescription and over-the-counter), or lifestyle is.