According to the FDA, side-effects from warfarin* are not common, but they can occur. Warfarin may turn your urine red-orange; this effect is harmless. If you think your urine contains blood, call your doctor immediately. Tell your doctor if any of these side-effects are severe or do not go away:
· headache
· upset stomach
· diarrhea
· fever
· skin rash
If you experience any of the following side-effects, call your doctor immediately:
· unusual bleeding or bruising
· black or bloody stools
· blood in the urine
· tiredness
· unexplained fever
· chills
· sore throat
· stomach pain