Any new illness may affect your INR in various ways. Illnesses that may have the greatest effect include those which involve:

• Diarrhoea.
• Vomiting.
• Fever or infection.
• Loss of appetite.
• Jaundice.
• Medicines you may use to treat your illness.

If you become sick with a fever, the flu, or an infection, call your doctor. Also call if you have diarrhoea and vomiting which lasts for more than one day.