Nausea, loss of appetite, or stomach/abdominal pain may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. This medication can cause serious bleeding if it affects your blood clotting proteins too much (shown by unusually high INR lab results). Even if your doctor stops your medication, this risk of bleeding can continue for up to a week. Tell your doctor right away if you have any signs of serious bleeding, including: unusual pain/swelling/discomfort, unusual/easy bruising, prolonged bleeding from cuts or gums, persistent/frequent nosebleeds, unusually heavy/prolonged menstrual flow, pink/dark urine, coughing up blood, vomit that is bloody or looks like coffee grounds, severe headache, dizziness/fainting, unusual or persistent tiredness/weakness, bloody/black/tarry stools, chest pain, shortness of breath, difficulty swallowing. Tell your doctor right away if any of these unlikely but serious side effects occur: persistent nausea/vomiting, severe stomach/abdominal pain, yellowing eyes/skin. This drug rarely has caused very serious (possibly fatal) problems if its effects lead to small blood clots (usually at the beginning of treatment). This can lead to severe skin/tissue damage that may require surgery or amputation if left untreated. Patients with certain blood conditions (protein C or S deficiency) may be at greater risk. Get medical help right away if any of these rare but serious side effects occur: painful/red/purplish patches on the skin (such as on the toe, breast, abdomen), change in the amount of urine, vision changes, confusion, slurred speech, weakness on one side of the body. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.