What are any symptoms of inr of 5.1?

Headache?Go to ER!: Hit your head with a hammer and you'll find out. The INR indicates how more likely you are to bleed (for whatever reason). It doesn't cause symptoms on its own. So if you are careful and don't cut yourself or fall over into a dry riverbed, etc you should do fine. Hopefully, you were advised about what to do about your medication. An INR of 5.1 isn't so bad, so don't worry, unless something bleeds