What you have is a classic case of a doctor ordering warfarin but not having the slightest idea about how it reacts to dosage changes.  First, there is so little difference between the complication rates between an INR of 2.3 and 2.5 that there was no rational reason to keep her another day.  Second, she was obviously tremendously overdosed to make her INR jump from 2.3 to 4.6 in one day.  Third, an INR of 4.6 almost never requires a two-day hold of warfarin without checking the INR.  This is certainly true for someone in the hospital where it is simple and cheap to do the required test.  In the average person, the INR will decrease by about half in two days.  A drop from 4.6 to 1.9 is exactly what anyone knowledgeable about warfarin would have expected to happen.  You will do your wife a big favor if you print off my free monitoring chart from http://warfarinfo.com/monitoringgraph.htm Use this to keep track of her INRs and how much warfarin she took over the past 7 days to get this INR.  Then you will have some idea of rational use of warfarin and can make a point against irrational changes such as she has been experiencing.